Conflict between pagination and post query

This refers to a previous ticket:
https://pickplugins.com/question/conflict-between-pagination-and-post-query/#single-answer-30257

There is a conflict between the post query (set to a specific category) and the pagination. The pagination loads all the other categories while I have only chosen one specific category for this post grid: http://dragesund.com/collections/nerdrum/ That category is in this case "The Nerdrum Collection". Why is it loading other categories and how can this be fixed?

YOU REPLIED:
"Can you please clear browser cache or deactivate any cache plugin you installed. also, try to deactivate others plugin one by one to check if any 3rd party plugin causes the issue."

I RESPONDED:
"Ok, so the thing is that I have not selected a specific category for this post grid because this post grid is supposed to be the same on all the category pages.

Here are three category pages and they all use the same post grid:
http://dragesund.com/collections/nerdrum/
http://dragesund.com/collections/lady/
http://dragesund.com/collections/grim/

And it works fine, as it is only displaying posts from the respective categories. The problem starts when I hit the LOAD MORE button.

Is this a solvable problem? It would be very tedious for my client to add a new post grid every time she creates a new category."

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PLEASE NOTE: You have a problem here at the PickPlugins forum because you never respond to replies in the support tickets.