My process is started, despite WSDL returned an error. How can I know, via WSDL, that process was or wasn't invoked? 
Detailed explanation of this problem:
 * The process used in test is very simple: Start -> launch IE with specific website -> Enter data in search field & click search -> sleep 5s -> close browser -> End
 * Process always outputs False (hardcoded in, not related to issue)
 * Process is invoked via WSDL (exposed process), using two resource PCs (http://[Resource_PC1]:81**/ws/ProcessName & http://[Resource_PC2]:81**/ws/ProcessName ) 
If I invoke 6 processes in a couple of seconds (3 per single resource PC) I get these SOAP responses:
Resource_PC1:
 * 1st process: Proper output ("Applicationfound xsi:type="xs:boolean" xmlns="">false")
 * 2nd process: Fails ("Couldn't create session - The requested operation is not permitted, because the license currently in use does not permit it.......")
 * 3rd process: Fails ("Couldn't create session - The requested operation is not permitted, because the license currently in use does not permit it.......")
Resource_PC2:
 * 1st process: Proper output ("Applicationfound xsi:type="xs:boolean" xmlns="">false")
 * 2nd process: Fails ("Couldn't create session - UNAVAILABLE")
 * 3rd process: Fails ("Couldn't create session - The requested operation is not permitted, because the license currently in use does not permit it.......")
Sometimes I get 2 successful outputs on single machine, but in general it looks similar to this.
PROBLEM: I can see screens of both PCs - browser was launched 4 times (2x on each machine). Session manager also shows 4 new, completed, records (see screenshot).
QUESTION: How can I know with 100% certainty, that process was invoked or not? Why, despite error was returned, process still ran? 
P.S. This error does not occur if some timeouts are added (e.g.: "Start -> sleep 30s -> launch IE with specific website -> Enter data in search field & click search -> sleep 120s -> close browser -> End"), but this definitely is not a solution.
P.P.S. BP version: 5.0.21
P.P.S. Object, which launches browser or performs search, run mode is set to €žBackground€œ. Process is published.