“Also, is there a chance your total orders exceeded the number of shares you have? It may be cancelling orders as you add/move around new orders.”
Answer: Nope, nothing of the sort.
Interestingly, TD cancelled one of my trades years ago only to re-instate it and sent me an apologetic message. I believe they had blamed it on a system glitch.
As far as T and C, I’m not aware of anything having changed. In support of this, I had recent events (not related to ENZC) where trades were cancelled due to corporate action or because the sell price was considered too high based on market activity - and I was notified.
Oh, and TD allows for GTC (Good Till Cancelled) trades to be set with a maximum expiration date of 6 months ahead.