When you open the Temple, the display of town income only shows the first digit of a number in the thousands.
For example, it shows just a 7 when the actual value is 7,208. If you adjust the number of priests (even back to the original value), it shows the correct value.
I also have a town where the income is in the hundreds (583). It displays correctly at first, so this bug only happens for numbers over a thousand.
