Thai - Cambodian Visa stamp to new passport

[mpa]

My situation fits here methinks. Newcomer in forums as well.

To get to the point, before reentering Cambodia from Thailand, I applied for a new passport in Bangkok. After a fortnight I was notified that my new passport is ready for pickup so I left Cambodia in order to collect it from the Bangkok embassy and get back again.

At the borders I presented both passports with the Thai exit stamp in the old one. The Thai officer asked for some additional docs given by the embassy in similar circumstances and he also mentioned that the embassy officials should have canceled my old passport when I received the new one, which unfortunately it wasn't the case. To cut things short, they let me pass by stamping my old passport so I entered Cambodia with the same passport which expires in October.

I emailed my embassy in Bangkok and they advised me to go in the local immigration office to pass the Cambodian entry stamp in my new passport.

In about two weeks from now I am planning to leave Cambodia for good and go to Thailand and Malaysia afterwards or fly directly to Kuala Lumpur, however I'm still worrying. What if things don't go as expected? Thanks in advance for any info.