Got a DataBase SQLite error

I started Anki and got:

An error occurred. Please start Anki while holding down the shift key, which will temporarily disable the add-ons you have installed.
If the issue only occurs when add-ons are enabled, please use the Tools > Add-ons menu item to disable some add-ons and restart Anki, repeating until you discover the add-on that is causing the problem.
When you've discovered the add-on that is causing the problem, please report the issue on the add-on support site.
Debug info:
Anki 2.1.35 (84dcaa86) Python 3.8.1 Qt 5.15.1 PyQt 5.15.1
Platform: Linux
Flags: frz=True ao=True sv=1
Add-ons, last update check: 2020-11-01 09:24:21

Caught exception:
Traceback (most recent call last):
  File "aqt/", line 87, in _on_closures_pending
  File "aqt/", line 59, in <lambda>
  File "aqt/", line 76, in wrapped_done
  File "aqt/", line 101, in on_future_done
  File "anki/", line 34, in begin
  File "anki/", line 229, in db_begin
  File "anki/", line 244, in _db_command
anki.rsbackend.DBError: DBError { info: "SqliteFailure(Error { code: Unknown, extended_code: 1 }, Some(\"cannot start a transaction within a transaction\"))", kind: Other }

I have four add-ons:

  • Hierarchical Tags 2
  • Ignore accents in browser search
  • Incremental Reading
  • LPCG LyricsPoetry Cloze Generator

Please note that I don’t have any deck nor notes generated by the Incremental Reading add-on at the moment of the error. Besides that, I restarted Anki (without holding shift), and the error didn’t occur. Moreover all add-on updates were already checked that day (info in the log), so I assume they were the last version available at that time.

As a final note, I’d say that my collection seems intact (I can’t know by sure since I have quite a lot of cards, but the magnitude is the same as last time I opened Anki, and no deck seem to have been purged).