'Another Installer is Currently Running' error when running dependency installers

So I'm using ExecWait and installing 3 things, dotNet 3.5, vcredist_x86 and Microsoft PIA. dotNet 3.5 is running silent, however sometimes during install when PIA begins it will fail and say another installer is already running. I thought ExecWait would wait for vcredist_x86.exe to finish before beginning the next process. does anyone have some ideas?

ExecWait always waits for the child process but it does not wait for grandchildren.

https://asawicki.info/news_1597_inst...mand_line.html has a list of switches for the CRT installer.