Different italicisation behaviour from Glyphs 2 — bug?

More italicisation questions! This is probably bad methodology, but to keep the exclamdown as a component in an italic font I paste the exclam then flip it twice. I notice, however, that on opening a Glyphs 2 file in Glyphs 3, these are now backslanted (I forgot to take screen grabs, and have now fixed this and saved over). I don’t do this often, but often enough that if I don’t catch it on an updated font it’s going to cause issues.

Place component [Command shift C] of exclam or question and then rotate 180º. Glyphs 3 will the correct side bearings.

I shall look into using that method in future, but the specifics of my question here is how Glyphs 3 handles Glyphs 2 files, and if it would be possible update Glyphs 3 to honour the original’s intent. This would prevent possible errors when updating old files.