I think the screws I've added will solve the problem. Not perfect, but much better. Again, I have this problem big time on my 2017 rear bumper cover nearer the tail light assemblies. Placing a floor jack under the rear valance, using a thick rubber pad to protect it, and slight up pressure will push the bumper cover into place, but cannot get the cover tab to clip to the actual hook that is part of the actual mount that is screwed to the body is near impossible. I did a basic disassembly of the bumper cover form the wheel well around to the tail light, just one 7mm bold and a push pin allows you to snap the cover off the under member. The last two clips near the tail light are not hooked at all, nor can they be. It seems as if the mount assembly is too far in, or simply too thick below the hooks, preventing the tab slot from engaging the actual hook. Same thing on both sides. Something is wrong with either the parts, such that they do not interact together as they should, or perhaps the positioning of the actual mount? I don't know what this thing is called, but it is black and has the hooks molded into it, and I am calling it the bumper cover mount. I developed a fix last night adding my own screws in the area hidden by the tail light assembly. The tail light comes out very easy, just three 10mm nuts, but the issue of the tabs not mating to the hooks in the mount drove me crazy and I removed the bumper cover up to the license plate area. Ford needs to take a look at their molds, tolerance stack ups, or assembly process. I had to file down he mount, basically making it thinner in order to get the cover tabs to engage the hooks. I also found that the rear mount was not tightened at the factory, this is the mount immediately below the left tail light.