Has anyone recently traveled with an old and new passport in hand to Kualar Lumpur?

My husband had to recently get a new Australian passport as his old one had a bad stamp from some dodgy school that cropped up during the Covid years.

On the 31st of March [Friday just gone] my husband left Thailand on an old passport that expires today [April 2nd] and he was hoping that the Thai Embassy in Kl would put the tourist visa stamp into his new passport [especially considering that the old one is now non-usable as of today].

So, my husband left Thailand on the old passport and then entered Malaysia on the old passport and is now concerned that at the Thai Embassy in Kl that they will think it strange that he has a brand-new passport when his old passport still had two years validity on it and a few spare pages left.

Has anyone recently been through this experience at the KL Thai embassy?

Any feedback would be helpful. Thank you.