Tapes may cross national lines once they are in shipping/distribution channels. For example, B&H Photo and Video often offers film that was nominally packaged for Europe. And gray market goods are common in high tech and photo, at least inthe USA.

If the tapes are giving the described problem - get ride of them. However, if not, them may be the European stock was OK.

Don I don't think it's worth the worry, if you have those defective batch numbers anywhere on the planet, just dump or exchange them.

The worry whether shipping also stuffed it up, you try them they seem Ok but later they decompose is just not worth it.

Cheers.