flukey

From fluke +‎ -y.

flukey (comparative more flukey, superlative most flukey)

Lucky.
- 2018 June 24, Sam Wallace, “Harry Kane scores hat-trick as England hit Panama for six to secure World Cup knock-out qualification”, in Telegraph (UK), retrieved 24 June 2018:
  For once, at a World Cup finals England could enjoy themselves, cut loose, score a bucket-load of goals, and giggle at the fact that Harry Kane’s hat-trick goal that makes him the tournament top goalscorer was a flukey deflection off his heel.
Unstable, prone to rapid and unpredictable changes.
We would have got to Spain already if it wasn't for the flukey wind.

lucky — see lucky

unstable, prone to rapid and unpredictable changes

English