The HDRP currently has a problem where surpassing the 24 lights per tile limit causes tile artifacts in/around the offending lights. In this example I have 72 lights stacked ontop of eachother to give a reliable example of the issue that can be repeated in multiple versions from empty projects.
This problem also occurs when looking through multiple light volumes even if less than 24 actually intersect as can be seen in this example with the cluster debug "show volumes option enabled. even though the lights are equally spaced they still behave as if they are intersecting at certain angles
I can understand the need for a limit of lights in games, but this behavior is very detrimental to using Unity for architectural renderings where we often have many lights near each-other or wide angle shots that end up with the lights behaving as if they were intersecting just because of how many are in that camera’s view.