From Microsoft's paper on their new derivative-based regex engine (RegexOptions.NonBacktracking):

Incidentally, the result for Rust further highlights the importance of avoiding outliers, as it would be a clear winner if not for the pattern [a-q][ˆu-z]{13}x. The crux of the pattern is that [a-q] denotes a subset of [ˆu-z] much like in the classical example a.{13}. This pattern is challenging for DFA based engines, as the loop can be entered multiple times, leading to a 2^13 factor in number of states. Optimizations in NonBacktracking have made this pattern no longer visible as an outlier.

It might be worthwhile including this case in the benchmarks.