Since V1.3.47, I have noticed that legendary items no longer drop from legendary enemies. It has now reached the point where legendary drops rarely happen, so it gets progressively worse.

I'm level 32 and I do not have that problem. Most Legendary enemies drop legendary items more then 50% (think it's actually more like 75%) of the time just like before the patch. I've killed 3 within the last 2 hours and all dropped their special item.

I'm not noticing a decrease in legendary drops either. For me it has been about the same. Today I ran into an already dead legendary mirelurk hunter with raiders clustered around it and even that one that I had no hand in killing had a legendary weapon (A lucky plasma pistol.) Maybe something happened with your game? A mod conflict or something? Or it might have to do with the in game luck stat (or maybe the luck of the player.)

Like the others here I haven't seen any change myself. Legendary drops are happening the same for me as they always did.

I play on Hard difficulty and don't use fast travel. I get a Legendary enemy and Legendary item drop on every encounter whether it's part of a quest or random encounters outside. I'm at level 62. I was kind of annoyed last night because my current character only wears metal armors and can only use projectiles weapons (same rule apply to my companions and settlers). After running between 2 minutemen quests locations I have quite a few Legendary items that I have to sell.

So, I don't see anything different after the patch.