Using mb-custom-taxonomy and custom-PosType I have been some data "corrupt". Even if you delete the taxonomy and recreate, whenever I try to see it from the frontend appears "page could not be found".
I need to clean the data that leaves your database plugins to start again. Reinstall does not work.
It's very simple. In a new installation you create a posttype with the builder. If after you edit them again and change the slug, automatically all the frontend querys stop working and get error 404. It does not matter if you delete and create again, this falls somewhat corrupt and not deleted. It does not matter if you reinstall the plugin does not work.
In the end, I reinstalled wordpress and started from there. That if, I lost a few hours and a few days.
You sell some plugins for developers and you have a support that takes six days to reply. I do not know what you think about your target audience, but if your support is this, certainly gives it.