Learn English – Why is “lawyer” widely pronounced “loyer”

Hyperbole comes from Greek ὑπερβολή, via Latin. When English adopts words from other languages, it often keeps both the spelling and pronunciation close to those of the origin language. Since other languages have different spelling conventions from ours — in particular, in many languages, a final e isn’t silent — many borrowed words have disparities like this: compare forte, mocha, jalapeno, etc.

(Another common cause of disparities between spelling and pronunciation is that spelling is much more resistant to change, so a spelling is often a fossil of an older pronunciation: that’s where things like the silent l in walk, talk come from. But that’s not what’s going on in this case.)

It's hypercorrection.

Germans can pronounce the English 'v' just fine, they happen to write it as 'w'.

So the freshman English learner from Germany will pronounce (using English orthography/pronunciation) 'water' as 'vawter'.

They'll then start to associate the 'v' sound with a mistake.

So the sophomore reasoning, which results in fixing some problems, for a German speaking English will be to change anything that sounds as 'v' to a 'w'.

Even though 'vector' is written with a 'v' (and pronounced that way in English, a German might over correct and 'fix' the 'v' and use the 'w' sound instead.