Bed Rail Cap Bulge

Likely something I just gotta rip up and troubleshoot but my truck came with the OEM tonneau cover and I sold it and swapped bed rail caps with the buyer. When I put the standard rail caps on the driver's side had a bulge that I didn't realize before dropping the bedcover over it. There definitely wasn't anything under the caps and I don't think it's down to it being out of place because it's got a ton of weight on it that would force it in and the rest of the cap and the passenger side sits right.

I let it be for a while but it seems it's definitely letting some water in and I know it's most likely I just gotta take the bed cover and tent off and get in there to see what's up but was wondering if anyone else has had this issue and anything I should know. Would just like to have a plan and know if I need a new part before taking everything off so I only have to do it once.

Also, does anyone has any third-party rail caps that help with water sealing or close off those front corners?

Thanks all!

 

i read something in a post regarding the corners.
apparently toyota makes a special part that seals off the gaps.
30$ each?
other posts mention filling the gap with caulking.
i cant understand toyota sometimes!

 

Yeah thanks I saw those, not sure if they fit with the standard bed caps or the only the ones modded for the tonneau