For all the parts where this BOM entry is blank: is the **LCSC Assembly** attribute set to **Yes** in your schematic? 

There's no such attribute on those parts. It is present though on parts listed with "Yes". See attached: 

@dmelentyev, Sorry but you need to go back to the library and check exactly where you got your symbols from. The part you have shown in the screenshot is not from the correct JLCPCB library. For JLCPCB Assembly, you can **only** use parts placed directly from the JLCPCB Assembled library. In you picture, there is an incorrect footprint C_0402 instead of **C0402**, and two important attributes, **LCSC Assembly** and **SMT Type** are missing: 

Ok, I will delete and re-add each component manually, there's not that much work in my case. OTOH, it might indicate a bug in easyEDA code. The history of these components is like this: 1\. I've added some capacitors from LCSC \(not assembly\) library and in wrong footprint \(too big\) 2\. Pretty much sure\, I've generated the PCB with those bigger components 3\. Using some of the managers in easyEDA \(sorry\, can't remember exact steps\) I've changed components/part numbers\, picking them from the \_correct\_ library\. 4\. Attributes \[most probably\] gone or not added 5\. I do remember issues with footprint not matching the selected component after replacing old one with a new from library\. I might have messed around with footprints and changed some of them manually\. Anyway, Andy, thank you for help!

@dmelentyev, I was being cautious when I said: "For JLCPCB Assembly, you can **only** use parts placed directly from the JLCPCB Assembled library." Of course that is not quite true because it is also possible to do what you have just described: place parts then edit their attributes to be that same as parts from the JLCPCB Assembled library but - as you have found out - it is very easy to make mistakes and end up with incomplete or incorrect port information. :)