was just about to post my video for the Scoring to picture challenge and got this message for the first time i think:
No more than 3 consecutive replies are allowed. Please edit your previous reply, or wait for someone to reply to you.
is this something new or has it been on the forum since the beginning?
I believe it came in one of the Discourse updates in the last year or two. Anti-spam function, usually tied to how fast you reply to yourself. So time between replies is important.
One of many “features” we may not have much control over it. We’ll look into it!
In the meantime, try putting all of your replies (like in the aforementioned thread) into a single post.
You can quote multiple people in one reply. 
I think I’ve seen that before on the Share Your Tunes thread, so I try to roll my replies into one post with a bunch of quotes instead. I just replied to you so you should be good.
Better practice IMO
yep, might have to consider that next time