Poor stropping technique might be causing your problem. You should use virtually no pressure, use enough tension on the strop, keep the spine in contact with the strop at all times. Do you think it could be something with your stropping technique? how many passes do you do?

Since you are new to this it takes you longer to shave which causes the lather to dry out. Only lather up small portions of your face at a time, that will keep the lather from drying.