Hi there. Well, it’s expected, because Crowdin MT doesnt work with regional dialects so far - only some languages are supported/ See the list in the in Resources → MT → Crowdin MT.
As not all European languages are now supported by MT, on my personal experience, with the most popular languages, in 99.99% of cases there should be no problems and the quality of translations is at a high level.
By the way, you can have both original Language + dialect in the project, just pre-translate the original one and dialect will be automatically translated also. I’ve seen sownehere here a link to the topic with that, here’s it https://community.crowdin.com/t/set-up-the-fallback-language-for-dialects/370