Appreciate the input, thanks Jehan!
Well I've definitely got the message about breaking my work up into smaller parts first, I'm doing that now and that does help, at least my work is intact..
I'm attempting to upload an xcf (one of the corrupted ones) to my Google Drive, my internet connection is not the fastest by any means and as the file is just over 2GB this could take some time (currently it's telling me it will take 4hrs 45mins!), after that I will link it on the bug report site you mentioned. As for the reproduction steps.. what I do is simply make some artwork, then add to it or modify it in some way at each step (layer) often employing plug-ins and scripts to enhance things of course.. sometimes completely changing views from one frame to the next .. all of this is usually problem -free, but like I've said before, once I reach that 2GB mark, things seem to become problematic and the newer saves can be corrupted, missing frames, disordered in some way.. hopefully by my keeeping them smaller in size that won't happen again.
Thanks for the animation tips, I'm not in any way, shape or form a serious artist, more of a doodler lol.. the stuff I produce (which I refer to as 'abstract animation', although I'm not sure that's a precise definition..) is usually just a lot of colourful patterns and weird effects put together with no real vision as such, I often complete a work, then use GAP to animate it, after which I make some adjustments and then put music or other sound to it.. here's an example of one of my latest efforts: https://www.youtube.com/watch?v=edCZ-ZpUgnE
(best viewed in 720p)
So, I'm not sure how else to achieve the results I want with animating without simply adding layer upon layer, to me this is similar to one frame following another frame and so on.. but maybe I'm wrong on this (I DO understand the concept of individual layers in general and how they work in relation to single images, and in fact some of the layers that I use as frames are themselves flattened images from multiple layers) - how would you approach it differently using GIMP as a base?
I'll update when the xcf file is uploaded... that reminds me, I'd better create an account on the GNOME bugzilla. site