Attribute limit

Hi, if I’m in Products > Edit Product > Attributes tab and selecting e.g. 5x Attribute, each has about 50 Values used for variations (so 250 in total) and I press save button, then the attribute values are shrink to 243. The limit number is not always the same, it’s different when using different set of Attributes. When your plugin is deactivated I didn’t reach any limit even I had around 1000 Values in total. What could be the reason please? Is there some limit set somewhere? Thank you.