Impress 6.2.4.1 When editing gradients, they usually don't get saved in the document, but sometimes do. When Adding gradients, they never get saved in the document

Presentation with different gradient backgrounds. Adding a gradient with a new name, it appears while open but after closing the document it does not reappear when re-opening. (In an older version, they used to be saved and appeared in all documents.)
Changing the gradient background on a slide-by-slide basis works while the document is open, but after closing and re-opening, SOME of the backgrounds have not been saved correctly. Some do save correctly, and I haven’t been able to figure out why some do and some don’t. The incorrect ones revert to the background on the first or master slide. I have tried:
(1) Adding a gradient under Slide/Properties/Background/Gradient. These disappear completely after closing and re-opening the document.
(2) Changing the gradient by hand for each and every slide under Slide/Properties/Background/Gradient
(3) Duplicating a slide with the correct gradient, and saving
(4) Saving after every single change

The only way I got presentations to save correctly was to create a new one from the ground up, inserting the slide backgrounds in order, and then copying and pasting the content on each slide one by one.
So it appears to be an issue with editing existing backgrounds.

Tips or a work-around would be greatly appreciated!

(This was a problem in earlier versions also, no answers: Impress 5.2.3 5.2.4 slide background gradient lost after save and why are background colours lost on save?)

Can this help?

Thank you, I haven’t made the gradients templates because I don’t want them in other documents. I only wnat them to be saved in the current document.
I believe I’ve used all the other procedures listed in the FAQ. I tried adding gradients from the master slide, and for some reason today LO crashed and when I opened it again, the newly added gradients were all gone. Just the same as what happened before.

Please:

  1. Don’t forget to mention relevant data, like document format (ODP? PPTX?) or operating system;
  2. If you have found a regression, please file a bug report, attaching a sample file, and mentioning specific steps required to reproduce the problem with the sample.

The “regression” part is inspired by the “In an older version, they used to be saved and appeared in all documents” part of your description; it seems to contradict somehow with “This was a problem in earlier versions also” - but of course, given that you didn’t mention the older version number where it used to work, it might be fine.

I’m using Impress, odp on Ubuntu 18.04 (downloaded, not the snap version).
I had this problem during the past 6 months, when I was using Ubuntu 18.04 with two earlier versions of 6.2.
Last year I was using Ubuntu 14.04, with the standard repository version(s) of Impress, and that’s when the backgrounds I saved used to get saved fine. I guess I will try to file a bug report.
The references were from other people using even earlier versions, 5.2, who had the same problem but no answers.
Thanks for your help!

Filed bug report tdf#126347

This has been fixed in 6.2.4.1. Thank you!!!