rtlsdr_close freezing in latest windows build

[bobasaurus]

I noticed an error when using the latest 32-bit 2019/07/14 windows build from here:

https://ftp.osmocom.org/binaries/windows/rtl-sdr/

Calling rtlsdr_close just blocks/freezes indefinitely. On program exit I'm calling rtlsdr_cancel_async (successful), then joining the sampling thread (successful), then calling rtlsdr_close (freezes).

This was not a problem with the old "RelWithDebInfo" version of this library (built on 2014/1/24).

[bobasaurus]

If it helps, I'm running Windows 7 x64, but building a 32-bit program with the 32-bit dlls. Using a nooelec nesdr smart, driver is WinUSB v6.1.7600.16385 installed with Zadig.