My developers recently told me that if the Special Price in Magento on a simple product is left blank for a selected market, the next time the product is saved by repository (i.e. image save method) it treats this field as NULL.
This results in Magento overwriting (native mechanism) this field, taking the price(special price) value from Default Store (if it is set there).
Which results in overwriting the special price;
I have never had this problem before, and I wonder if this error can be caused by changes made by softwarehouse or if this is actually a native Magento behavior