I succumbed to the temptation of increased performance and did not expect such unstable operation of this version, I gradually transferred my project from the fourth version of the engine and never before had such big and catastrophic problems. Errors just appeared out of thin air, I spent several days to understand that the project was crashing due to nodes in one of the blueprints that were not even connected to execution.
Today it killed me that I changed an array with a Boolean data type to integer and tried to use it, the engine broke down, after overloading I did the same thing, but saved it before compilation, it crashed again and I could no longer run the project due to cyclic overload with the error - “BPW_EntrySPlayer_C of type ArrayProperty(BoolProperty). Loaded 4 bytes but expected 10. Package”.
As it turned out, I lost this bluprint forever along with part of my work, because even after moving the file to another project, it crashed when I tried to open it. I really regretted that I decided to move my project, and most importantly, I had already done some of the work before I realized that it was a big mistake and even the release of version 5.4.1 did not help me in any way. Now I will have to spend a lot of time restoring the work done for 5.3.2, so I want to warn you to refrain from doing this for now.
Generally a good idea to wait min 6 months for transferring projects, testing is another matter somebody’s got to do it
i generally try to wait a year on things like this
Always and i mean always have a backup at minimum and preferably use revision control i can’t even tell you how many times I’ve killed a project and been lucky to recover even half of it with an entire days work 
All the good practice advise aside, thank you for the warnings
some of the biggest changes were to the animation system if your Bp arrays have anything to do with that may be part of the why
No, it was working with a widget.
A widget is not directly an animation…
what i meant more specifically is
the entire Blend space system was changed which relates to your Character BP in some major ways behind the scenes
I didn’t have any problems with animation, perhaps because I had already finished this part of the project and don’t touch it much.