when I add one value to a custom field it got added twice in JIRA.. Can you help here

Question

I am adding a value to a custom field but when I add it is coming twice and if I delete also both the values are deleted. can you help here?

Doug Swartz · Answer

Also. What type of custom field is it?

unknown · Answer

A screen shot would help

Nic Brough -Adaptavist- · Answer

Sorry, could you explain "it is coming twice"?  I understand something is being duplicated somewhere, but I can't imagine what it might be.