I have this symbol set that shares a few symbol elements. The elements they share get weird scaling issues when they're "bothered" (moved, scaled, any way of interaction with them). I should also mention they specifically have constraints set to not scale with their respective constraint groups (it wouldn't be the expected behaviour either way since that affects scaling that happens after they're disabled, not the scaling that has happened before the fact). Undoing doesn't fix the bug either, requiring a document restart. This makes the issue quite problematic in case you haven't saved in a while (could just force close Affinity to get the autosave but I guess but that's a terrible workaround)
Here's a video of the issue and a file. The issue is present in both release and beta.
2019-08-14_23-26-04.mp4
Symbols_bug.afdesign