The recent regex change on version 2.5.6 in this line:
https://github.com/riot/compiler/blob/master/src/core.js#L133
Matches text incorrectly. It matches from the word "import" to the last single or double quote on the entire tag, not to the end of the import.
Example:
https://regex101.com/r/Isww62/1
Previous regex behavior:
https://regex101.com/r/Isww62/2
This problem breaks any tag with ES6 imports inside.