Volume fluctuates

Hi all I need your assistance

I’m currently new to recording. I am using cubase le 10 to record church audio for services.

When I mixdown my audio to mp3, wma or wav files there seem to be in certain parts of the recording the volume fluctuates…like a compressor. I’m not using any compression.

I tried every possible way to mixdown and still get the same outcome.

Please advise what am I doing wrong or possible things I need to do before mixdown.

Your assistance will be appreciated.

Thank you