You say you have recreated the FTI. Did you delete the folder from the server? I have found that you need to delete the folder & its contents before a recreate really does create a new index.
ARe you searching from an agent or using the FT Search? If the search then it will only operate on the view that you are in when you start the search - an agent searches the whole database, however it can get a bit stressed and you might need to break a search down into small bits.
When you search for “8x1” it returns documents because there are documents containing the “word” 8x1 – hyphens are seen as word breaks in the index. You need to use a wildcard (? or ) in order to use a particle of a word for a search. [TechnBenennung] CONTAINS “8??” and [TechnBenennung] CONTAINS "8" would both return two documents in your example.
