What is wrong with this LIKE in an Query?

i am facing a strange problem using a Like operator in a query.

I want to query fields (String) containing values like ‘VG004-0383-543830399298’

Now it seems that the query only delivers results if the LIKE condition contains a non-numeric character.

For example

LIKE '%0383%'

does not find the entry.

LIKE '%-0383%' 

finds the entry.

Whats wrong?

Thanks in advance,

Johann