Nodes on sidebar cannot be drag-dropped

I'm having a weird problem. A bit of background first: I have a configuration node that gathers information of the current flow's nodes and calls some external APIs, after which another fresh flow is created with the additional information from these APIs.

Now, when I install this node, in all flows that I have open, none of the sidebar nodes can be drag-dropped. I mean they are perfectly draggable, but once I drop them they do not remain on the canvas. It's as if the canvas has suddenly become read-only.

I've already checked: uninstalling this node solves this problem. Does anyone have a clue as to what could trigger such behaviour? I'm unfortunately not able to share the code here because it's still proprietary.

Have you checked the browsers console for any errors?

Thanks for the reply. Yes, I have. Neither Firefox nor Chrome show any errors. This behaviour is present in every computer that I tried.

Does anyone have any input at all? Thanks.

You mentioned you can’t share code, but are you at liberty to tell which node causes this behaviour?

Of course, this is a configuration node. This node reads the information of the current (as well as other existing) flows (from a GET to the Node-RED admin API) and then calls other endpoints elsewhere in our environment to perform some calculations. Then, we create a new flow based on the output of these responses, by POSTing the admin API again. I'm having a hard time understanding how this functionality could impact the editing area (canvas) and the nodes.