Hi Tobias,

Greetings to you!

According to Salesforce doc (https://help.salesforce.com/articleView?id=000006771&type=1):


This message is displayed because of a security feature called Collision Detection. 

Collision Detection is used to prevent a user from saving their record changes if the record they are editing has been modified since the edit began. This feature cannot be disabled and is in place to prevent possible data loss.

If there is some action (e.g. trigger, workflow, flow, etc) that changes that record while a user is currently editing it, Collision Detection will throw this error message.

This also occurs if one User is editing but another User is just looking at the record, and then the User just looking at the record does not refresh the page before starting their edits.

In the Salesforce Classic UI, this error is only thrown when a different user edited the record.

In the Salesforce Lightning Experience UI, this error is thrown when any user (including the logged in user) edited the record.

There's an idea which is active on the success community with a similar discussion for which you can upvote so that it gets available in the future.

https://success.salesforce.com/ideaView?id=08730000000BpkAAAS

https://success.salesforce.com/ideaView?id=08730000000l3hUAAQ

Also, please refer to the below links which might help you further with the above requirement.

http://mysalesforcestuff.blogspot.com/2016/03/the-record-you-were-editing-was.html

https://success.salesforce.com/answers?id=9063A0000019b5jQAA

https://help.salesforce.com/articleView?id=000240899&type=1

I hope it helps you.

Kindly let me know if it helps you and close your query by marking it as solved so that it can help others in the future. It will help to keep this community clean.

Thanks and Regards,
Khan Anas