I just finished improving my glass chest piece to 90 armor vs 68 unimproved. When I went to enchant it with fortify health using a grand soul gem at dragon's reach and it shows me that once I enchant it the improvements will be remove setting it back to 61 armor. My smithing skill is at 73, light armor at 42, and enchanting at 74. What am I doing wrong?
This is a known display bug, where the enchanting table reads the item's base values instead of checking to see if the armor has been improved with the Smithing skill. It does not actually lower the equipment's armor rating - complete the enchantment and view the finished item and you will see the armor is still as powerful as it was before being enchanted. The preview simply shows the values as if the armor were unimproved.