I'm sure you've learned the 'hard way' that it's not good to mix brands/types of sealer. Whether it be accidental or 'intentional', the results are unpredictable (until the results are seen.)
I'll guess that one brand is a Sand-based Filler and the other one isn't. The purpose of the sand is for a non-skid 'effect'. I happen to have it on my driveway which runs up 4' over a distance of about 40'. It's great because, when it rains or when after shoveling snow, you have some traction. W/O this type of Sealer, well, you're likely to slip a WHOLE heck of a lot more often!
The Sand Filler needs to be stirred CONSTANTLY. (The Instructions on the bucket will tell you.) I use a broom handle for the job. Having followed the instructions for 7 buckets, I had no problem. I stirred a lot and did the job, beginning in the cool of the day and ending in the heat of it. (I did 72' about 6 years ago, and haven't had to do it since.) I, too, waited 4 seasons before I did it.
I guess all I can say is try to make do w/what you have. There are a few ideas I have about 'fixing' it but it will involve work. You could wait until the 'bad section(s)' come loose, then power-wash that area clean, and re-seal w/the 'matching' sealer. Or, if it doesn't come loose over time, just go over it w/the matching sealer. No matter what you end up doing, it's BEST to clean the area(s) in question w/a power washer to insure that the sealer will STICK to a clean surface. Dirt, grime, and the like will PREVENT new sealer from sticking. If you have more ?'s, you know where to find us.
My best to ya and hope this helps.
Jay J -Moderator
PS: I don't mean to sound 'heavy'. I'm writing for your benefit (even if you know), as well as the benefit of others that may read your Post ...