Imperial Measurement Categories and Filters

Hi,

I hope someone can help with this, as it’s driving me nuts…

I have 2 kinds of product measurement (categories) set up in my store – metric ie. 12mm and UK imperial ie. 1/2″.

I also have product filters set up for these measurements and both kinds of measurement display perfectly well in the filter bar (along with applicable product counts).

However, only the metric measurement filtering returns any results, the imperial measurement filtering returns nothing – “No products were found matching your selection.”.

Do you know of a reason as to why this would be please and more importantly how I can resolve this issue? ??

Many thanks