After upgrading to Unreal Engine 5.5, I’ve noticed an issue with inherited Blueprint variables, but it only affects certain variables. Specifically, some variables created before the upgrade behave unexpectedly. When I change their values in a child Blueprint, the parent’s default value is retained instead of the child’s modified value. Additionally, these specific variables reset to their defaults whenever I restart the editor.
This issue doesn’t affect all variables. Variables created after the upgrade seem to work as expected, and some older variables still behave normally. However, for the affected variables, I’ve confirmed that they are marked as instance editable and not private.
I’d appreciate any insights into why this is happening or potential solutions. If this is a known bug, I hope it can be addressed in a future update.
Thank you.
I reported the bug: case # 14731198
After upgrading to 5.5, I made several edits to the project. When I attempted to downgrade back to 5.4, everything broke—including the default level. I couldn’t migrate my work on the actors from the 5.5 project to 5.4 because the actors themselves were incompatible (even the ones I didn’t edit). As a result, I had to spend an entire day manually copying and pasting all the changes I had made, which was both time-consuming and frustrating.
I want to leave this just in case
We just realized that we’ren having the exact same issue: certain variables do not seem to be inherited properly anymore. In the editor everything is working fine, it’s the shipping builds that have problems.
In our case we’re using blueprints for wall pieces in a dungeon, and sometimes they simply are not shown at all, it seems to be random.
So we have parent blueprints - some of them might have been created back in UE 4.27.
It’s basically an actor with 2 static mesh components. We use those to switch between fully and partially visible walls, to ensure the player can be seen at any time. The children are simply referncing different wall designs.
Initially we thought that the children are not loaded at all in shipping builds as nothing could be seen.
At some point I checked the parent blueprint and realized that while it held all the nodes to take care of blending between the two static meshes, the parent itself had no meshes assigned.
So I assigned a dummy sphere and a dummy box to those components and guess what: that’s what is shown instead of the meshes that the child actors have assigned.
I already deleted the static mesh components in the parents and recreated them, but that did not help unfortunately. My next test would now be to re-create the parents and children from scratch with new file names, to ensure there are no leftovers from the old stuff.
Did you find any solution? We realized that every blueprint that has static or skeletal mesh components seems to be affected (e.g. weapon pickup we placed in the levels), but the problem only occurs if the blueprint is supposed to be loaded when the level is first started. If we spawn something in the running game, the variables and their references seem to be fine.
EDIT: I recreated all parents and children, got to a point where I thought it was a problem with specific meshes or materials as sometimes it helped reimporting he FBX files and creating new material instances for them, but in the end it all collapsed and behaved completely random again.
Any help would be very much appreciated!
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Also, I noticed that when I reverted the entire project, there was a float variable in the parent class called “Lifespan.” However, every time I restarted the editor, this variable reverted to its default value. After some trial and error, I realized that Unreal Engine was interpreting it as the built-in variable “Initial Lifespan” without any warnings. Therefore, I recommend checking your variable names and considering renaming them, as it may resolve the issue.
We confirmed the issue happening for static & skeletal mesh as well as geometry collection components.
For now we were able to circumway the issue by adding variables for these components on the parents and on the child blueprints, we assigned the same values(meshes) used for the components to those variables. On begin play of the childs, we load those meshes dynamically from that soft reference and that makes it working for now…
For some reason I can’t edit my last message anymore, but it migh be worth mentioning that this seems to only be happening with level instances being involved.
