Sorry if already mentioned, I didn't find this in the forums.
The morale tooltip on my home planet (morale at 41%) reads as follows:
41 = -25 population, -58 taxes, +18 buildings, +6 native bonus.
Naturally enough that all adds up to 41 (assuming you start at 100). The problem is, if you check the Planet Details screen, it shows I have +25% to morale (in green lettering) - presumably from anomalies I've found and the Entertainment Network on the planet.
I would expect the morale to be 66, not 41 - bug?