We are running into problems with our unit tests which use the standard pricebook. When they are run separately they work fine, but as soon as we do a "run all" several tests fail with message:
System.DmlException: Insert failed. First exception on row 0; first error: UNABLE_TO_LOCK_ROW, unable to obtain exclusive access to this record or 1 records: 01s0Y000005PZuEQAW: 
We have been experimenting with the SeeAllData, but either with it on or off it will cause this error. As far as I can see we are not updating the pricebook itself, but we are setting it's Id on our quote / order line items. So maybe it is being updated because of references being added?
Anyone ran in a comparable issue or knows what might be causing this issue?