"old" open orders are returning pending_cancel during market hours

New issue for me with Paper today is that pending_cancel is showing up during market hours. Until today, it only occurred outside of market hours and extended hours.

/orders?status=open&limit=500

I’m seeing extended_hours orders from 09/05 showing up as pending_cancel during market hours today.

Is this new behavior, a bug, or is it somehow that I missed seeing this until today?

With the behavior as is, is it safe to assume that the extended_hours will be “instantly cancelled” in the next extended hours session (pre or after market)? If not, I guess the best approach is to (attempt to) cancel all orders a few minutes before the end an extended hours session so that the market session is not blocked from trading. I want to avoid over-selling at a specific limit price related to extended and market hours orders being duplicates.

Update: The same orders remain stuck as pending_cancel even in extended hours.

aefa66ef-1238-4115-94f2-8241a8e545ff MSFT BUY 1 213.15 9/6/2020 2:37:55 AM
4a3caac7-f4be-485e-932d-8ad7c05e4823 MSFT SELL 10 219.6 9/5/2020 5:47:53 AM
d9852d62-5790-4bdf-b1fc-75c226478425 TSLA SELL 10 493.7 9/6/2020 2:37:55 AM

Using the web UI, these orders do not display in https://app.alpaca.markets/paper/dashboard/orders.

When I click Cancel All Open Orders, they are listed in the Order Cancellation Submitted.

The button then grays out. When I create a new order, the button lights up and invoking the button again lists the new order and those same 3.

Apparently a backend issue with those orders being stuck?