Problems with dsm output in QGIS since last update

Since updating to Version 2.1 I’ve had problems using the dsm output in QGIS. I processed one job, then did the update, then processed a second job.

When I try to use the raster calculator in QGIS with the second job the output is usually “Nan” if I try to process the whole raster but, I get a proper result if I process a smaller area within the raster.

My aim is to difference two rasters but I have problems even if I try a simple calculation like dsm + 1.

I have no problems with rasters I processed before the update.

The result is the same on Mac or Windows.

Puzzled!?

Apologies, after some research it appears this is a problem with QGIS. After reverting to the long term stable release I’ve had no problems.