after first patch? you must mean BEFORE LAST patch, bcs thats what 9.1.5 is
and yes, they do that quite often, in both bfa and legion pretty much all restrictions they put in with base game were lifted later during the expansions (and before then too, although not so often), some of them sooner, and sure, some of them later in the expansion, BUT! what you seem to "forget" (or ignore as it doesnt push your predetermined opinion) is theres not much SL content left, as far as we know 9.2 and thats it, so when should they lift those restrictions, in next expansion? ofc they do it now, before the last major patch...
remember corruptions vendor for example? didnt even take another patch, they did it in the same patch corruptions were added...
so trying to pretend they dont do that is either complete ignorance or outright lying