Issue with blueprint compilation

Hey everyone,
Im having a lot of issues with Engine/Transient references not allowing me to save my blueprints.
i have deleted many of my files and started again, and this seems to work for some time but its a pretty horrid workflow.

At the moment im having an issue where when i open my project one blueprint is uncompiled. if i open it up and compile it i have no errors. However if i mouse over on of this function calls before i compile i can see it has an error calling a function from another BP. For UMG i know using interfaces for everything tends to fix these problems but i really want a clean project solution for others to easily read, and it feels like a dirty hack.

I would like to give as much debug information as possible, but i’m afraid i’m not entirely sure where to start; so here is everything i have.

Here is the error before i compile. Note that if i compile this BP the error will go away and the project runs as normal (until a random issue with transient/engine ref not allowing me to save a blueprint).

My message log also has some errors related to the use of structs and some of these functions.

Paste bin: http://pastebin.com/zSZtHPxW of log.

This is right after opening the project, its worth noting that this BP cant be saved, and the white widget in the background should not be white, it has graphics and other user widgets but they are not rendering. its like it failed to load. This user widget also holds a reference to JCWItemSlotContainer (that has the function render child widgets). i am unable to save this BP, but if i remove its user widgets nested inside it (there is two of them) then create them again, and link them up to there respective code it works fine till i reopen to project.

i have managed to fix the issue with

by Opening JcInventoryPawnInterface and editing something, compiling, saving, chaining it back then saving and compiling. This interface has two functions but is used pretty much by every single UMG widget. I still have transient issues and can not save the blueprint here

here is my new compile log,

and this one was from my saved/log.log

also another one of my widgets will not save (it is used as a child in JCWItemSlotContainer, so there’s defiantly a pattern)

This one does not give a Engine/Transient error.

i understand this issue may be too project dependent. can someone suggest how i can frame the issue in a way that makes sense or give me a clue how to debug this for more information? the issue seems to be with blueprint structs in 4.9 .