Expiration Date or Exp Date will display the date for that specific membership transaction. Current Expiration Date displays the date for the most recent membership transaction for this specific constituent.
On the Memberships grid in the Details View, you will see all the membership transactions. If a constituent has multiple membership transactions, you will see an Exp Date for each transaction and the constituent's Current Expiration Date, which will be the same in all of their transactions.
For example, we are currently in the year 2025 and I am a member who purchased a 12-month membership on 1/31/2024. I then purchased a renewal on 1/29/2025. On the 2024 record, my Exp Date would be 1/31/2025 and that membership has expired but my Current Expiration Date on that row would be 1/31/2026 because I have purchased a new membership since that original transaction. The new transaction that occurred in 2025 would have an Exp Date of 1/31/2026 and a Current Expiration Date of 1/31/2026.