After activation of integration, mapper showing warning, "variable doesn't exist"

Content

We are facing an intermittent issue in all OIC instances, where after activation of the integration mapper start popping up a warning message, with the message "variable doesn't exist", thus the integration run is failed and going into the global fault.

There are no changes done in the mapper and this issue is very intermittent. Once I used "regenerate endpoints" through the integration navigation and re-activated, sometimes it disappears and sometimes not.

please help.

Version

20.1.1.0.0 (200113.1400.33493)