Messages not displaying AM/PM

You are sending these messages via E-mail/SMTP to the e-mail address format used by the two different companies (e.g. phone-number@company-specific-domain.net).

When you receive the SMS from the SMTP gateway on your Verizon phone you see meridian indicators (AM/PM).  When you receive the SMS from the SMTP gateway on an AT&T connected phone, you do not see the meridian indicators (AM/PM).  Is that all correct?  I have the following additional questions:

1. If PM, is the time the correct 24 hour value, or is the PM just truncated (i.e. does 2:00 PM become 14:00 or just 2:00)?
2. Are you using the same model phone and the same Messaging app?
3. Have you tried sending the same message from one phone to the other, both ways, to see what happens?
4. Can you share screenshots of the original message and the resulting texts?

1.Yes its 24 hour format - 2020-11-20 14:40:00

In AT&T phone its displayed as 2:40

In Verizon phone its displayed as 2:40 PM which is the correct way of displaying.

2.Yes same desktop application is sending same messages to different phones on different networks using the respective network gateway domains. For AT&T it is [email scrubbed].

Verizon,T-Mobile/Sprint all work fine and are displaying AM or PM as appropriate EXCEPTING for AT&T.

As above 2:45 is AT&T it should be 2:45PM for 14:45

As above 2:30PM is Verizon and is displayed correctly when time is 14:30

Please assist.

Thanks