Maybe they were initially meant to be identical. The Asian factory shutdowns and global shipping delays during the pandemic could mean that TT was bumped off from receiving any of the initial production run of MPM-12 and the stock all went to Hasbro who had the priority. Since TT no longer had to have the same production run with Hasbro (this particular toy anyway), TT being TT they decided to make the toy slightly more screen accurate (whenever/whatever they could) and changed the colours slightly. Maybe a little non-adveristed bonus for those fans who waited the extra 10 months. Just a little theory of course.
Would have cost them if they were to have two different paint jobs in the same production run. Wouldn't really cost them extra since the TT production run ended up being separate.