This problem is not related to eBay email and is maybe related to the way you are viewing your eMail.
If you use outlook or other similar program, try to reinstall it.
If you use service web as gmail, you can try to disable all add-ons because it may cause bug like the one you are expecting.
If it does not work, you can try to reset your browser configuration to Default Value but beware because it may delete your saved bookmark.
Hope it can help to solve your problem.
