This bug specifically affects accounts with websites operating in unsupported currencies, where Bing Ads relies on automatic conversion to supported currencies. Due to a recent glitch in Microsoft Advertising, the system has stopped recalculating conversion values accurately.
For instance, a conversion value of 100 CZK is being displayed as 100 EUR in the interface.
Hopefully, Microsoft will fix it soon.
The bug was discovered by Tomáš Hanáček.