A large width value crashes the app on saving

Hello, I’ve lost some work because the app started crashing when saving one document. It turned out I had an abandoned glyph with a crazy width value, probably caused some time ago by the metrics formula bug. The file saves well in 3511, but crashes the app in 3514 and 3515. Changing the width to something more reasonable lets save the file. Some safeguards against crashing would be appreciated!

Attaching the file:

Save test.glyphs (58.4 KB)