Disappearing formulas after deleting some and dragging to hotkey bar

[Thorgat]

That was reported by Sina at HZE, her english is not very good and she asked me to bring it here. She told me that she deleted a few formulas on purpose (in sum she has around 300 formulas) and since this time she several times has lost formulas she tries to replace but looses often again.
They seem to disappear only when she drags the formula to hotkey bar. Next login the icon/button at the bar is still there but the formula gone from the knowledge book. As she can't afford to loose more formulas she is afraid now to drag a formula again to the bar of course.
Any other informations from her needed or what she should try?

[AmonGwareth]

I suspect there is a problem with the character inventory, but without additional information or being able to see the character in the database I cannot say.

- Amon