utf8 string braking one the way to web service function

When passing utf8 data to a web service, the data breaks and it gets to the function with weird symbols after every chunk of text, always in the same location. this problem does not happen always. when adding a character that changes the length of the string -the problem disappears.

this problem happens only when sending utf8 characters. when sending English letters the problem does not happen

i tried checking if the web service function brakes the text, but its developer said he gets it with the weird symbols

i expect the string to either always brake if there is an encoding problem, I want to get to a state that the string will get to the web service function with no weird symbols