Hi ,
I experienced the same issue with various blueprint classes (but with version 4.7.6). All variables that were reseting on startup were inherited from a parent BP. So far, it seems to be fixed for me by placing the parent BPs in the level (they were just only in the content browser before).
Maybe this is also helpful for you!
Hi mgreg,
Do you have any reproduction steps I can take to reproduce this on my end? If we can nail down some way for me to recreate this I’ll be happy to put in a bug report!
Interesting observation mgreg! In my case the affected properties are inherited from the class’ parent’s parent. The immediate parent’s added properties and other properties from the grandparent stay intact.
I added an instance of both ancestors to the level, we’ll see if they fix this.
Unfortunately, that didn’t solved the problem finally. After a crash of the editor I had to reset all variables. (But simply restarting worked before.) Sorry!
(I didn’t restore anything after the crash, just opened before saved map.)
Hi everyone,
Has there been any update that may help me to reproduce this on my end?
I’m currently monitoring a placed instance of the parent class to see if it produces data loss like its child. Stay tuned.
Hello ,
all I can tell, what I have done in my project, is that I have multiple child-blueprints of some parent blueprint. All are placed as instances in the level and have editable variables (some inherited from parent, some own). The types of these variables range from Integer to other blueprint classes. I set values for these in child and parent (before placing parents in level, only children had values set).
The weird thing is, that at some instances some variables are reset to default and on other instances of other children classes they stay as I set them (the same variables).
I don’t know, what else I could say about that issue. Maybe I have too much blueprints in my project?
Can you send me a sample project this is occurring in? It would be easier for me to see what may be occurring if I had assets to look at. If privacy is a concern you can send them to me in a private message on the forums.
Hello ,
no problem. I can send you my project. But I don’t know how to write a private message in this forum. If I go on your user page, there is no option to do that.
If you go to the forums and press “Notifications” in the top right of the screen, then press “send new message” and put the recipient as " ". Post a link to an FTP service such as dropbox containing your project and I’ll download it from there.
Hello ,
thank you for explaining!
My newest obersation is, that all variables stay as I set them. As for now, I don’t know which changes I made, that cause the fix.
As soon as I can I will upload for you a old revision of the project, where the problem should occur again.
HI everyone,
I was able to reproduce this and have entered a bug report, UE-21201, to be assessed by the development staff. The error is specifically for inherited values that are set to default values and cannot be edited in 4.9, however I am currently working on several bug reports of values resetting in packaged and launched projects that may be tied to this as well.
Hi there,
Any updates on a fix for this? I believe I am suffering from the same issue.
BP child class objects that have been placed in a level are getting a subset of their editable variables reset to the parent class defaults, seemingly at random. I usually notice it after opening a level in editor.
It has been plaguing me for a while, so any advice or updates would be a huge help.
Thanks,
Try this in 4.9.2, there was a fix for another bug report, UE-20258, which this bug report ended up being a duplicate of.
Hey i suffer from this bug too… problem is that i had 20 maps, with many blueprints and properties manually edited in them… and sometimes… somes properties reset… 1 week of work lost (or more) so i wont redo all my map again till this bug is fixed…
I feel so bad right now 
but quite happy that is a know bug now…
its not fixed on 4.9.2 i suffer from this. this a huge bug, i had 20 maps with many blueprint with property manually edited and… here we go the random propertie reset BOOM
so many hours of work lost
-Properties concerned: an array of vector, a boolean, an enum, a reference to an actor.
-Step to reproduce: i dont have exact step but i didnt suffer from this bug before i reworked the code. was working fine when it was simple blueprint based on actor. i reparented most of my blueprint to have parent and made them to be child. Since i did this, i have now some childs properties (and always the same properties seem to be impacted) are reset when i restart editor
-Project information: limited to this project as i use parent&child for the first time
-Project created in 4.8 if i remember
-i think i dont have circular references (circular reference mean that i have a reference of my child in my parent and a reference of my parent in my child?)
as usual sorry to not have steps to reproduce this, but for sure it happened when i rearranged my code to parent&child
i will try to make a blank project with parent&child bp, and then try to see if i can reproduce the bug and send you this project
Ok i found why it does reset for me
i often do change in my blueprint parent, doing some cleaning, some renaming, and here we go… renaming a variable in parent reset the property of childs placed in level
is that normal behavior?
tell me this is a bug, because i love to rename and clean my blueprints 
Hi , I was able to reproduce this on my end and have entered a bug report, UE-22557, to be assessed by the development staff.