As seen here: https://www.reddit.com/r/feedthebeast/comments/bqbag2/arent_unintended_mod_interactions_the_best/

This could be easily fixed by making the Merchant invincible, no?

Or maybe breaking/disabling (or turning it into a "abandoned market") the market when the merchant isn't present! This will make it also more realistic, when the merchant isn't behind his stall then he can't sell anything to you.

Something like the new 1.14 minecraft update with the blocks that turn the villagers into their profession.

There will be an option to have merchants count as children which should prevent them from generating most resources, but it will be disabled by default.