Why isn't *all* debit card activity immediately shown on my online statement?

I’ve noticed that my bank (Wells Fargo) can see some “approval requests” on my debit card that I cannot see online. For example, if I make a T-Mobile payment, that day and the next I cannot see any sign of it when logging in to my WF account. But if I call T-Mobile they say “yes, you paid, it’s been processed” and if I call WF they say “yes we can see the approval request but it may take a while for you to see it on your online statement”.

Why is that? Isn’t this a security problem that I cannot immediately see all activity on my debit card? Is this just WF that does this or other banks? I’d be Ok to swap out WF if it’s just them doing this.