Typing in {R_t} over {R_0} = {%PSI_t} over {%PSI_0} the vertical spacing between the fraction bar and the greek letter %PSI_0 in the denominator is missing.
Looks like a duplicate/highly related to bug 65774 too me. Therefore I'm marking it as duplicate. @Bug reporter: if bug 65774 is fixed, and you still can reproduce this behavior, please reopen this bug. Kind regards, Joren *** This bug has been marked as a duplicate of bug 65774 ***
Problem solved by substituting {R_t} over {R_0} = {%PSI_t} over {%PSI_0`} for {R_t} over {R_0} = {%PSI_t} over {%PSI_0}.