err with transfering a property from rest response to post request json body

Hello everyone,

I have  a REST project and I have some problems during my one testcase. It has 3 steps - first get request, which goes through then a property transfer of one value from the response of the get request to a json body of POST request, then the post request. When I run the whole test case, the property transfer happens but the post request does not - while the value is being transfered to its json body request the json body deletes some of his part. When I run just the property transfer it gives me an err saying invalid json. the json body is valid though, by itself without the porperty transfer the post request goes through and  I also checked the json in online json validator. Any idea whats going on? thanks!