I’ve used sketchup in a hobbyist form for years now. I was on Make desktop, but decided to try the new free web version. I’m plagued with disappearing entities. Typical scenarios:
Select COPY. Start dragging copied item. Drop it. Looks good … and, GONE. Just gone. Hit undo and it re-appears.
Choose an item from the warehouse. Drop it. Looks good. … 1 second later it’s gone. Hit under and it’s back.
Select MOVE. Start moving. Somewhere during the move it just disappears. Hit undo.
Happens every session, many times per session.