Lens focus ring sticky degrading rubber

[bobakman]

I have EF lenses some that were included in my kits and another the 70-300 that I purchased separately. 
I have noticed that the rubber outer covering of the focus rings only not the rubber on the body of the lenses, have deteriorated becoming sticky and soft with age.
These lenses have been stored when not in use in either my camera gear bag or separate lens cases.
These are the specific lenses and date of purchase below.
I am the original owner and have always had clean hands when using these lenses never any chemicals such as Insect repellant or perfumes or cologne on my hands.
I have submitted service requests for all of these lenses to Canon and am awaiting a resolution.
Has anyone else had this issue with their Canon Lenses?
Video link here: https://youtu.be/tK24Y3TMTm4
Thanks, Bob

EF-S 18-135mm f/3.5-5.6 IS STM. 2013-01-22

EF-S 18-55mm f/3.5-5.6 IS STM. 2013-06-03

EF 70-300mm f/4-5.6 IS USM. 2013-06-03

[bobakman]

I actually used Isopropyl alcohol to remove the residue so I could order those rubber pieces and found out that the focus rings  are NOT rubber but hard plastic. Pretty bad though when hard plastic starts turning soft on the surface.
This would explain though why the rubber on the body is not affected.
So the pieces on Ebay would basically stretch over I assume the existing focus rings so if they do get sticky again they would be covered and not exposed.
Bob