Your footprint almost certainly abuses graphic lines as copper tracks. This has been an old hack in KiCad, but as KiCad improves the old hacks tend to break or get removed altogether. In older versions of KiCad, graphics on a copper layer was simply ignored by DRC, while in newer versions DRC recognizes graphics and always keeps a clearance from it, and therefore you can’t reach the pad. It is the only option for KiCad, because graphics do not have net info.
This feature has also been abused for years for net ties. When KiCad became aware of graphics on copper layers the net ties broke, and this was temporarily fixed with another hack, by putting the words “net tie” in the keywords of a footprint. (Open a net tie in the footprint editor and then: Footprint Editor / File / Footprint Properties / General (tab) / Keywords
In the link below I experimented a bit with the pad edit mode. In this mode graphics are attached to a pad and become a part of it, and therefore KiCad and then it becomes a part of the same net as the pad.