Oddly enough, we tried everything but didn’t solve your problem. There are a few caveats:
– We do not support Woocommerce plugin, using this plugin may lead to conflict with the theme
– The newly created Custom Taxonomy has a rather large ID, for example:
Language ID: 686895253
Plaatsen ID: 686895230
I don’t know if you interfered with customizing these IDs. Normally when creating taxonomy, this ID is just 2 or 3 numbers.
The search problem only occurs when filtering by taxonomy, so I think the cause is that these taxonomy are abnormally generated.
You can create a new white wordpress on this same hosting, then send me an account so I can test it with a demo from our side to check the cause.