Posting workaround for posterity in case the fix gets postponed or something similar.
The reimport usually does not work with packed FBX files, even if you change the transform, you have to import mesh assets and animations separately and make sure you have your desired import transform set for both - it also must be same for both.
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importing skeletal mesh: tick off import animations - change import transform to X
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Importing animation: tick off “import mesh” - select skeletal mesh you just imported - change import transform to X
