Your roof is aluminum that we can see.
To the patch, the one picture you posted doesn't show us enough to know it's OK or not. And at this moment it might not be leaking. However on a roof situation, once it's leaking then things can go bad real fast. Key is staying ahead of the situation to not get to the leak stage.
The texture of your roof "looks" like someone did something with a coating in the past. The roof metal is waterproof, but the seams and the joints where roof vents, tank vents, moldings etc, that have flanges or screw holes which penetrated the waterproof metal is the issue. There is not a need to coat the entire roof unless pin holes are seem for some reason. But there is a need to have good sealants at seams and anywhere holes were made in the metal.
The issue now is, new coatings of any kind can be compromised if they are put on top of old not good coatings as they cannot bond to the original aluminum roof. If your patch is adhered good and solid on all edges, check and see, then OK its bonded and that's good and keep monitoring it. If the edges show signs of lifting, then that is the time to act before the lifting can get advanced enough to get to the hole that it was covering. That is a big patch they did for reasons not known.
If it comes to needing to correct the patch, getting it back down to the aluminum will be the challenge. Scraping with a dulled metal putty knife (every edge rounded) and a heat gun may soften the old material so you can get it up. After scraping, mineral spirits rubbed with a rag might soften up the little hairs of leftover material. The unknown is, what do they use and what will cut/soften/dissolve it and not create issue worse? If the heat can soften it and allow it to come up, then mineral spirits might help. If the heat will not change it at all, then you need Plan B and I'm not sure what that is at this point until we know more about what it is.
I know mineral spirits will work on aluminum, as I have use a lot of it and no adverse effects on the aluminum. But it does leave an oily residue that requires a high flash cleaner to remove the residue before putting a sealant down. Rubbing alcohol, naphtha, lacquer thinner works. Caution to not use Acetone as it will take any paint off on the camper it touches.
We have had other club members report they uses Dyco 20/20 roof sealant on their metal camper seams and roof penetrations. https://dycopaints.com/products/dyco-20-20-seam-seal
I myself have not used it.
There are sealing tapes what will bond to the metal roofs and create a very good seal too that lasts. They cost more, take a little learning curve on appling, but will bond and seal small holes and seams. But they have to bond to the clean base metal and primer can be used in suspect areas that are not totally clean. Eternabond is one brand I have used with very good results. EternaBond
I have used a lot of that material on RV roofing, mainly on rubber roofing but it is rated and will bond to clean metal as well. It can deal with the flexing and conditions of and RV environment which is different than a stationary mobile home. I have used E bond to create a watertight seal between aluminum siding and aluminum moldings on my camper slide system and from the roof to the aluminum moldings. And on my neighbors all one piece aluminum Coachmen camper. It does cost more, but applied right it is a permanent repair. There is a need to add a slight film of Dicor caulking to the exposed edge of the E bond sealant tape. This is not needed for water proof needs, but to seal that exposed edge from dirt sticking to it. If you want to go this route, let us know and we can explain more with pics.
Hope this helps some. If you need more, please add some more pics of the area in question so we can see what you are up against better.