very strange noises

Okay, so last night i was doing my daily tank clean, damped moss, put food in the bowl and handling for 10 mins, and as i was holding mella (female) she made these really werid noises, i wasn't a hiss more like a growl? i can't explain it, i assumed so was angry with me and put her back in her tank and she sat in the same place i put her for about 10mins, normally she walks off into her cave. She made this noise while just sitting in my hands while i was have a look at her for anything bad stuff, stevie also came out his cave to have a long and she made the noise when she saw him (i think) any suggestions as to why she made this strange noise? am i doing something wrong?
Thanks

Some of them are just vocal that way. I have a male who when he is exceedingly happy makes a sqwaking noise. He also makes that noise when he wakes up and is ready for his evening of adventure.

Sometimes they make a noise like a chirpy frog type croak when they're displeased with something. Eros makes that noise when he's done with deshedding his toes in a bath and I'm handling him to get a better look at his toes.

Sometimes they make that noise also when their body is bent a certain way, like I have one that barks when he twists around to lick his behind or something. He makes the same noise when I'm lowering him down from my hand where his front legs are reaching out to touch the ground.