Question about sealing on the inside edge of shower panels

[AVR2]

I'm re-sealing the shower put in by a previous owner with more enthusiasm than skill. I know that as a general rule, you shouldn't seal along the interior horizontal seams where the shower frame meets the tray, only the external ones - unless the manufacturer's instructions say otherwise.

The interior seams have been sealed (with a grey sealant rather than the white used everywhere else, so possibly by someone else at a later date). Since I don't have the original installation instructions and have no idea who made the shower, should I remove that sealant, seal the outside, and then see what happens in terms of leaks?

The main reason I'm resealing (over and above the mould) is that there is a leak from the outside of that seam.

 

[denso13]

should I remove that sealant, seal the outside, and then see what happens in terms of leaks?

Yes, or just seal the outside first and see what happens. That might just push water elsewhere though if the sealing on the inside remains.

 

[polesapart]

original installation instructions and have no idea who made the shower, should I remove that sealant, seal the outside

Yes. Remove inner sealant. See what happens when shower is used.
If necessary, then reseal outside. See what happens.