Facebook Ads Manager Changes

For my clients I normally schedule content on Facebook about a 1 - 1.5 weeks in advance and with the scheduled posts instead of boosting them I turn them into ads since we are trying to get engagement & eyeballs on my client’s Facebook page. Last week I tried using my scheduled posts in business suite as an “Existing Post” option, but they wouldn’t show up. I tried even using the Post ID given in business suite but it kept coming up as non-existent. I was able to speak on the phone with my marketing manager pro at Facebook, and they told me that they are no longer allowing you to use scheduled posts for an ad and that they have to be active on the page in order to be able to use them. Does anyone know when this was announced or when they made this change? Have you had a similar experience? I just feel like Facebook didn’t give any sort of heads up about this change and it’s making my job a little harder since I manage about 5 different Facebook Pages who all run ads for every post. Just looking for advice or if anyone has been going through a similar experience!