it might be awhile before this issue is solved or not at all. (it’s free afterall, but some help is appreciated)
Might want to use all-in-one-seo pack as an alternative, had no issues with it previously.
thankfully i had a backup done before i updated to v3.5 in the event something like that were to happened (and it did!) so uploaded the previous backup and yoastseo is working fine now on v3.4
u could do that if you had.
Moral of the story: Backup whenever you make any changes esp updating and using new (free) plugins! i guess u can never be too safe…