Right now I'm adding fields to some of our layouts. At first, some field types were used up to their limits, so I've started finding and deleting some unused fields from the past. The total available field number in the "Custom Fields Left" list title does increase when I first delete a particular field from the "Unused Fields" list and the number in the "Available" column in that list also increases for the deleted field type.

But the system warns me that the limit for that particular type has been reached when I immediately try to add another field of the same type. I see that the numbers have reverted back to their former figures even if I've already deleted some fields from the "Unused Fields" list when I check the "Custom Fields Left" list after the warning.

I've tried to close and open the layouts page, refresh the complete website etc but the result didn't change. I need a fast solution to this problem.