It appears that the OpenCV package found [here](https://github.com/its-pointless/its-pointless.github.io/blob/master/files/dists/termux/extras/binary-aarch64/opencv_4.0.0_aarch64.deb) seems to have the same bug as 3.4.4-1, reported here: https://bugs.archlinux.org/task/60855