valve adjustment fixed ticking noise 95%, now intermittent rattle same area

2007 Accord Sedan V6 – 137k miles

Car was gifted from father who maintained it very well, consistent oil changes, scheduled maintenance all done on time, etc.

He always used conventional 5w20 but I started using Mobil 1 HM Full Synthetic thinking it would help prolong engine life. After this switch to synthetic, it developed that infamous “lifter” ticking noise that went away when engine warmed up so I didnt think anything of it. About a year later I noticed it got worse, much louder and took longer to go away with warm engine, traced it to the area of #5 cylinder with the mechanic stethoscope. Decided not to ignore it anymore so I did a valve adjustment. All intakes were right on point or barely loose at all. All exhaust were tight EXCEPT #5 cylinder had one of the two that was barely (and I mean barely) loose.

Car is significantly quieter now, no more ticking thank god but I hear a rattle that intermittently comes and goes. I almost sounds like the same ticking but much weaker.

Any ideas what would make this noise? Could it mean anything that one of the two exhaust valves were loose on only one cylinder?