Download Attribute Dropping - wishlist mod?

[HinterWelt2]

Version: 1.36-1.38a
Mods: Heavy down to none
Windows NT LELU 5.0 build 2195
PHP Version : 5.1.2
MySQL Version: MySQL 5.0.18-nt-log

Environment
I currently have three installed ZenCart stores running. All are download stores. YGN is a modified mall environment with over 100 vendors participating. KoboldQuarterly is a simple print/download store with some integration between ZC and PHPBB2. HinterWelt is a site with little or no custom mods.

Bug
Far more frequent on YGN (due to volume I believe with over 2000 products active) you will have a product drop its download attribute. It still allows purchase but then I have to go in and manually attach the download file.

Possible Causes
1. At first I thought it might be the mods I made to YGN but then it happened on the other sites.

2. Everything was marked Virtual Product. I have changed this today and we will see how it works out.

3. For a while, Wishlist mod was the culprit but that has been disabled and it still persists.

4. Some how registering "Disabled" and disassociating the attribute???

Solution?

Thanks,
Bill