Last week I spended 1500 seals to the guild - as seen in the contribution screen. In the Roster it showed 1492 seals. I don’t know, how many seals where really counted…
An explanation for the gold could be something like that:
You have 1234 Gold. In the screen where you contribute (normally 1000, 5000, 10000,…) you chose the last entry (don’t know exactly the name). What happens? I haven’t tried. But could end up you spent 1234 Gold. Could also be a counting error like with the seals.