I was playing Pebberly Heights and opened an expedition crate to find a Pristine Sarcofrogus. I noticed a very brief slowdown in performance but didn't think about it. I clicked send to inventory. I had an average Sarcofrogus in my game so I went to use that to Research it. I started the research and went to place my Pristine version, but it was not in my inventory. So, I left the level, started another level and then went back to Pebberly Heights and it was still not there. Decided I was bored with PH, I would deal with the missing item later and went to Passwater Cove to play with the aquariums. Very shortly after starting I got a crate and opened it to find an Average Coralsseum Ruins. I clicked Place Exhibit (instead of Send to Inventory) and went to place it and realized it was too big for the little area I wanted to place it in and needed to move some decorations around. I noticed the slow down in performance again and clicked to place the Coralsseum (which was red and couldn't be placed in that area). However, It DID place the exhibit (albeit on top of other decorations). I could not re-select it. I could not move other items 'beneath' it. So I decided to exit the level and re-enter the level. The level would NOT load anymore. My PC is a higher end performing PC and usually levels load up within 15-20 seconds. I waited nearly 3 full minutes and it still did not load. The 'spinning circle' in the lower right corner was spinning, the music was going, so it's not technically a freeze. 

I was able, with the help of Discord, to restore a previous save to I can continue playing all the levels. So I don't need any help with this issue - just wanted you to be aware of it.