Android WebView pixel scaling

Hi! I’m testing an app. Everywhere else (iOS, desktop browser) it renders fine, but Android WebView seems to use a pixel scaling method that makes some ad hoc rounding to whole number of pixels.
Eg., a 1px border between list items is sometimes thin, sometimes twice as thick. Text placement within a line is horrible and unpredictable.
Am I missing something very basic? Is any special configuration needed to make Android WebView render properly, so that 1 pixel is always the same size?
Thanks a lot!