From Paul Sorensen <paul at kc9asu dot net> via email:

With eng display mode set, if you enter:
1 exp 12 / 1 exp 8 =
You get:
100e+18
which should be:
10e+3

However if you enter:
1 exp 12 / 100000000 =
You do get the expected:
10e+3

It appears you are adding exponents instead of subracting for division.
But only if both numbers are entered in exponential format.

I first noticed it in version 5.5.45 which is included in Fedora core 4
distribution. I saw that version 5.6.31 was available, so I downloaded
and installed. Same problem.