So what I did was that I started checking the logs carefully, and I found out that any flow has a history with it and it redos all the changes no matter what, for example, if there were some old table in other instance that flow was referencing earlier in dev and now you have deleted the table and did the changes in flow, and same flow is promoted to other instance. All the changes are again created and deleted (with respect to flow) in the new instances, but in new instance you dont have that table and the error occurs in prod. Due to this, it will not successfully compile your flow, and you will keep getting that error.
My advice will be to create a new flow from scratch (the same flow) in dev instance carefully. Promote it to prod, and check. If no error occurs then you know that there was some problem with old flow compilation.
