DbError, InvalidStateError on Firefox

[armhub]

DbError. could not create transaction: InvalidStateError, A mutation operation was attempted on a database that did not allow mutations.

Tutanota version: 3.38.6
User agent: 
Mozilla/5.0 (X11; Linux x86_64; rv:62.0) Gecko/20100101 Firefox/62.0

Stacktrace: 
DbError. could not create transaction: InvalidStateError, A mutation operation was attempted on a database that did not allow mutations.> value/<@https://mail.tutanota.com/worker.js:1:398228
r@https://mail.tutanota.com/libs.js:32:9667
[22][22][22]c@https://mail.tutanota.com/libs.js:30:1608
a@https://mail.tutanota.com/libs.js:30:1496
[2]r/this.drainQueues@https://mail.tutanota.com/libs.js:30:1236

DbError@https://mail.tutanota.com/common.js:1:176592
value/<@https://mail.tutanota.com/worker.js:1:398305
r@https://mail.tutanota.com/libs.js:32:9667
[22][22][22]c@https://mail.tutanota.com/libs.js:30:1608
a@https://mail.tutanota.com/libs.js:30:1496
[2]r/this.drainQueues@https://mail.tutanota.com/libs.js:30:1236

Originally posted by @charlag in #657 (comment)

[charlag]

MDN says that it occurs when

The close() method has previously been called on this IDBDatabase instance.

Which makes me think that it's the same as #452

[charlag]

assume tested