See CR. Just a reminder, will be fixed soon hopefully.
See also bug 31676 comment 22
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Reverted out in https://gerrit.wikimedia.org/r/#change,5031
Submitted https://gerrit.wikimedia.org/r/5108 which disables this behavior.
since this fix was committed I close this bug.
r110988 was to fix a certain bug, but had as side-effect that it brakes @import. This fix was reverted and that other bug (IE stylesheet limit) has been re-opened.