Any chance duplicate detection is on? A vendor "accidentally" activated this on a log table, yes I said log table. This resulted in our plugin hitting the 2 minute timeout whenever we create/update records.
I found this best practices from MS. It basically states NOT to use batch requests unless it is for outside services.
Avoid usage of batch request types in plug-ins and workflow activitieshttps://docs.microsoft.com/en-us/dynamics365/customer-engagement/guidance/server/avoid-batch-requests-plugin