Space in ligature

Hi. I’m working on a underlined font. So my space is also filled with artwork. So far so good.
But when using ligatures suddenly my space bar design appears inside the ligature design.
Anyone any idea how to prevent or solve this?

What is a space bar design? Can you post a screenshot of what you are describing?

Generally it is a bad idea to force the space into a ligature. It can lead to unpredictable diverging behaviours in different environments.

I use the spacebar to make sure the underlining continues.

This will not work everywhere. You have been warned.

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

Update: This is a problem of the Adobe Composer. It does work as expected in the World-Ready Composer.