The separator character "^" should also match the end of text, as per the EasyList conventions. E.g. see https://adblockplus.org/filter-cheatsheet/. 

However, this fails currently. E.g the test case 
{{"page2^", kAnchorNone, kAnchorNone}, "http://example.com/page2", true},
in SubresourceFilterUrlPatternTest.MatchesUrl will fail.

There's also a TODO to this effect in the code - https://cs.chromium.org/chromium/src/components/url_pattern_index/fuzzy_pattern_matching.h?type=cs&sq=package:chromium