Error when creating card

Hi All,
I get the following error occasionally (1 per 30 cards perhaps) when I click “Add” after making a new card.
The error happens on multiple computers. I’ve tried the standard “database check” to no avail…
P.s. once I click the error away the card then saves normally…
Any help would be much appreciated
Thanks and best,
J

ERROR
Error
An error occurred. Please use Tools > Check Database to see if that fixes the problem.
If problems persist, please report the problem on our support site. Please copy and paste the information below into your report.
Anki 2.1.29 (bbff62bf) Python 3.8.0 Qt 5.14.1 PyQt 5.14.1
Platform: Windows 10
Flags: frz=True ao=False sv=1
Add-ons, last update check: 2020-08-11 21:31:25

Caught exception:
Traceback (most recent call last):
File “aqt\webview.py”, line 490, in handler
File “aqt\editor.py”, line 479, in
File “aqt\addcards.py”, line 189, in _addCards
File “aqt\editor.py”, line 591, in saveAddModeVars
File “lib\site-packages\anki\models.py”, line 87, in save
File “lib\site-packages\anki\models.py”, line 231, in update
File “lib\site-packages\anki\rsbackend_gen.py”, line 414, in add_or_update_notetype
File “lib\site-packages\anki\rsbackend.py”, line 265, in _run_command
anki.rsbackend.InvalidInput: InvalidInput { info: “attempt to save stale notetype” }

2 posts were merged into an existing topic: Error when adding a new note