Leaking PVC pipe & joist notch
I disagree that it is the joist causing the issue. When installed, they would have notched the joist so that the plumbing fit and there is no reason that the joist would have moved or expanded in size.

Related, the drain might not even be the source of the leak. While visually it appears that the leak is there, the problem might be elsewhere. Consider that you have tile and it is sloped to the drain. The tile is placed on backing, the backing is what provides the support and the slope. That backing is waterproofed. It could very well be that the waterproofing has failed and that the water is following the slope to the drain. Or that the waterproofing has failed at the drain.