Certain characters have outlines when bolded

I recently made a font using Glyphs (I am now using Glyphs Mini because my free trial ran out), and the font has no built in bold (I only made one weight). When I export and install the font, certain characters (like h and 1) have strange outlines when bolded. I’m not sure whether this is an auto-hinting error or what. Any ideas?

Bottom of 1 in normal weight next to bold with the weird outline:

How do you apply the boldening? Are there some overlapping paths.

Whenever I put the font in any program (Microsoft Word, webpages, etc.) and make it bold the problem happens. How would I tell if there are overlapping paths?

Can you send me the .glyphs file please to support (at) (this website without www). I will have a look.

@ forum.glyphsapp or just glyphsapp?

Just glyphsapp.com