New Bug Encountered:

[Yossi_Oulu]

The time it takes to confirm a formula in the expression editor has been increased lately.
Too much time to wait to be able to click on Save.
I rather not wait this extra few seconds, I know the expression is correct.
If you have to make few changes it is annoying.
It should allow save in any case even if it did not check it. Report the error later

[Steve]

The new column editor uses Expression Assistant, which until very recently did expression validation as you typed. Validating in real time like this is resource-intensive, and produced a lot of spurious errors as users paused in their typing.

To alleviate both issues, the automatic validations waits a moment before acting, which is the delay you’re noticing. You can just wait for it to activate, or Save your expression and immediately reenter the Expression Assistant. The expression will be validated immediately upon reentry.

A (sometimes beneficial) side-effect of the current behavior of Expression Assistant is that you can save an unvalidated (potentially invalid) expression.

[Yossi_Oulu]

I cannot save until the expression is checked. The SAVE button is grayed out.

This is the problem I’m raising.