Limit sell order "Filled Price = MKT"???

Perhaps this belongs in "beginners",... sorry and mods please move is so. But ... I'm confused about something:

I placed my first limit order to sell a small amount of BTC at ~$3400. I just checked and was pleasantly surprised to see that the limit order was filled. However, when I looked at filled orders to see if suffered any slippage, etc., all I see is "filled price: MKT". Also, the BTC I sold are still in my BTC wallet. I expected to see my USD balance go up by the amt sold and my BTC balance be reduced. What gives? Shouldn't I be able to see what amt of USD I received as a result of the sale? Why are there still BTC in the wallet when my limit order had me selling all in that wallet?

This was on CoinbasePro, btw.
(New to crypto trading and new to the forum, so I beg forbearance if this is a stoopid or misplaced question/topic. )