Edit: This might be an issue with the macOS's preview rather than the generated GIF itself. I realise that the uploaded GIF is identical but viewing it locally triggers the one frame lag. Currently investigating if this is the case with the other Macbook users
In macOS, the generated GIF will have the Wait appear one frame earlier. For example if you are supposed to type "This", followed by a Wait. The GIF will type "Thi", followed by a Wait, and then "s".
This is the GIF generated by macOS:

In contrast with the GIF generated by Ubuntu:

This is the following versions which might be relevant to the issue in macOS:
Version: macOS Catalina 10.15.3
ImageMagick Version: ImageMagick 7.0.10-19 Q16 x86_64 2020-06-12
Gifsicle version: 1.92
Edit: This might be an issue with the macOS's preview rather than the generated GIF itself. I realise that the uploaded GIF is identical but viewing it locally triggers the one frame lag. Currently investigating if this is the case with the other Macbook users
In macOS, the generated GIF will have the Wait appear one frame earlier. For example if you are supposed to type "This", followed by a Wait. The GIF will type "Thi", followed by a Wait, and then "s".
This is the GIF generated by macOS:

In contrast with the GIF generated by Ubuntu:

This is the following versions which might be relevant to the issue in macOS:
Version: macOS Catalina 10.15.3
ImageMagick Version: ImageMagick 7.0.10-19 Q16 x86_64 2020-06-12
Gifsicle version: 1.92