Just reporting a bug Ive observed reliably now in which my own runes of perplexity give me the 5 confusion on interrupt if I am interrupted by a petrification ability (IE Thief Basilisk Venom, Box O’ Fun, Or various Monster petrification abilities). Each time I noticed this happening I made sure to double check that there was not an additional source of confusion.
Hope this gets straightened out, thanks!
In short, If you have perplexity runes and are interrupted by something like basilisk venom that petrifies you, your own runes give you 5 confusion if they are not on cooldown.