I have a Favorite provider (whom I have yet to actually see) that had several reviews mentioning specific fetishes (i.e. GS, BDSM-related, etc.) and they were removed...and there were at least 2-3. Anybody have any idea why this might have happened??

scored too high and someone reported it to the Mods.  Fetish providers that DIDN'T provide BBBJ, DFK, Anal sex, or a doubles session are limited to a top score of 7 out of 10.  Peeing in your mouth is not a skill, so it doesn't qualify for extra points under TER rules, only the four activities I named above.  Massage providers are in the same situation.  Max score is 7 unless she gave you DFK AND a BBBJ, then she qualifies for a 9 maximum for service, or an 8 if it was only one of these two activities.  If the reviewer gave her more points than that, it is generally corrected by the mods, or returned to the reviewer for edits.  It won't go back up unless the numerical score matches the point total in the narrative.  

thanks for the insight!

There are many reasons reviews get removed.  You didn't state how long she's been in TER, how old or how recent the reviews were, whether or not she has other reviews that were not removed, etc.  

In addition to what CDL mentions it could also have been the case that the provider challenged the reviews you were looking at because she doesn't offer the services mentioned.

When did TER start deleting the reviews with scores that were not fitting with their system rather than just adjusting the numbers accordingly?

normally I'd concur but it wouldn't make sense since the reviews that were removed all had a lot of the same type of activities being done