DEL&GET Method 'sometimes' automatically changes to PUT Method.

DEL&GET Method 'sometimes' automatically change to PUT. 
I have some a post call followed by a few post & put calls.
Eventually I have 4 del calls. But these sometimes automatically change to 'put' calls. 

I can't figure out when or why it happens, any idea's? and how to avoid this?
Is anyone else having this issue?


Kind regards
Kristof