I don't know who started it, but there's a schizo theory that there's gonna be 3 SSRs again as well as a male summer servant (not a costume) this year because of Nasu's interference.
Apparently Olga wasn't supposed to be the anni servant, but Nasu pushed Lasengal to release her first and so the original anni servant will probably get released in summer, which many people still believe its gonna be Galahad, Romani, or Camazotz.
A lot of people point to summer 7 and 9 as examples of this happening before. For the former people point to an interview he did about the 7th anniversary how he wanted to put Arc in as soon as he was done with the first half of the Tsukihime remake, but since he couldn't find any place to insert her into the main story he decided to have her replace Proto Merlin as the anni servant and lasengal had to repackaged her as a 3rd SSR in that summer event.
The later is a bit more of a stretch, a few people are still convince that Space Eresh being the anni servant and Ciel being one of the two SSR summer servants was a last minute switch since to some people "anniversary servants are relevant to future events in the main story" (even though Tonelico hasn't technically appeared in anything besides lb6 flashbacks and assuming the Proto Merlin rumor is true, she hasn't done anything outside of events). Plus there's still still a lot of mistranslated interviews about how Sony/Aniplex forced Nasu and Takuchi to add Ciel or how OC3 was never meant to be combined with that Summer event.