The reason doesn’t matter... it is disrespectful to agree to a time and then not follow through.
I’d suggest you separate the what from the why in your mind.
Then think about how to handle it. Consider being firm about dates and times. Coparenting doesn’t work well if both parties can’t agree to follow through on those basic commitments.
Also document these events. Never know if you may find it useful down the road (“agreed to 8am. No response until after 9am.”)
