It apears to have been resolved by now.
The issue still appears on SO
The issue regressed here on MSE as well
I recently got access to the 10K-tools, and the inline tag editor, which I observed to crop the suggested tags by the boundaries of the tag box on my mobile, using the responsive design.
While writing this question on a desktop, I noticed the same problem on the ask a question page. See attached screenshot, where there should be a suggested design tag, but it is hidden.
When I use the inline tag editor on the question using FF on a desktop, it works as expected.
10K inline tag editor:
Using FF 68.5.0esr on Mac and using Chrome 85.0.4183.81 on Android.