Vishay is a massive supplier with many different branches, one of which focuses on small, discrete semiconductors such as BAT54W-E3-08. We’ve had some confusion recently concerning the top marking for this device - its datasheet lists the top mark as ‘L8’, but when received the products are marked ‘L4’. What gives?
Vishay has confirmed that this is an intentional, deliberate change and the ‘L4’ marking is correct. The product is not defective, and updates to their documentation for the product are in progress.