An event emited in recovery for stream is differs from originally emitted event

Hello,

We have an issue with projection. Suddenly we got the following error on projection:

An event emitted in recovery for stream CompleteOutgoingDirectDebitBatchProjection-result differs from the originally emitted event. Existing(‘Result’, 'C:1434074070034/P:1434074070034; OutgoingDirectDebitSettledEvent_V2: -1; OutgoingDirectDebitStatementReceivedEvent: -1; CompleteOutgoingDirectDebitBatchRequestReceivedEvent: -1; '). New(‘Result’, 'C:1433976867840/P:1433976867840; OutgoingDirectDebitSettledEvent_V2: -1; OutgoingDirectDebitStatementReceivedEvent: -1; CompleteOutgoingDirectDebitBatchRequestReceivedEvent: -1; ')

we use the 21.10.2.0 version of the event store.

The last change on the event store was extending an event and state of the event store, about one week ago.
Everything worked well for one week, and now we have this error.

Of course, we tried to restart projections and the server. and also tried to revert changes made one week ago, but still got the same error on the same event.

What does that error mean? And what can be the cause?