Strange product quantity, short description and search results

[gray]

1 - For some reason some products qty are set as N/A ?? no idea why or where. But I set them to 0 and everything is OK. Any ideas why this should happen.

2 – Some products came up with an error in that the short description was to long. Even though the shop was running all OK. It only threw an error when I went to update some product pages. Some of the short descriptions were shorter than the limit. Any ideas please.

3 – Some products within a category were not appearing in a search results. I could not find anything wrong in any of the data. Not in admin - products or in the actual database. I just re-saved the product, and then it started appearing in the search results ?? Any ideas why

I have gone back a few releases to an old installation using PS 1.7.5.4 and the problem has always been there, but it has only surfaced now I am using 1.7.6.1

I am just wondering how many other products have strange data.