MATLAB: Axes & subplot etc. return double instead of matlab.gra​phics.axis​.Axes

axesgraphicslinuxMATLAB

I need to use the Axes object to change my figure's appearance. But all the functions that should return 'matlab.graphics.axis.Axes' are actually returning 'double'. For example typing
class (axes())
returns 'double' even though a figure is created. My MATLAB is installed on Arch Linux, and otherwise works fine. There's another installation on a separate machine on centos, and that returns 'matlab.graphics.axis.Axes'. Can I fix this problem?