Ahhh... Tapatalk!
[Issue replicated here]
At the moment, it's a hunch, but I imagine Tapatalk doesn't know how to deal with the discrete search software we're running [it's an industry standard engine which offers extended functionality and improved performance]. I'll make sure this is brought to their attention and report back when there's news.
Thanks for your patience folks, and apologies for the inconvenience.
Rob.