Dragonfruit stem discoloration

[Plantinyum]

Hello, my dragon fruit plants seem to be getting this discoloration, the off collor parts seem to be a slightly lighter green than the main color of the plant. Does anyone have encountered this, on one plant I also have some dot like browner parts which at this point are internal. All of the problems i'm talking bout are on the newer ,this years growth, which has somewhat hardened. The plants are also having new growths which have no problems. The
 discollored parts seem to also be slightly more soft. My plants have been through periods in which they had softening of stems ,after which they got plump and stiff as usual . I have not fertilised them for tree months , also am keeping them on the dryer side now, their soil has little moisture in the top 5-10 cm, but at the bottom the soil is moist so I do not water them....
Thanks, if anyone has difficulties "reading " the photos, light me and I will edit them ...

[Rannman]

It looks to me like they are not getting enough sunlight. Are the plants being grown indoors under artificial light?

[Plantinyum]

It looks to me like they are not getting enough sunlight. Are the plants being grown indoors under artificial light?

right now they are in my house near a south facing window. Its winter here now, and they are definitely not getting enough light , judging by the new growth that is very thin ,compared to such that happens outdoors in full sun.
The last days here were gloomy and foggy without any sun , and now in tuesday we had a nice sunny day. Now at that time of the year I seem to notice that if we get a nice sunny  day , right after a few days of lacking any sun ,the vines get soft like they overheat or something. I dunno if the recent problems were caused by the bright sun , after four dark days . The sun when we have it ,hits them directly ...

[Plantinyum]

Heres the progress of the issue. The discolored tissue portions have become noticeably yellower and with little force from my part , they separate from the healthy tissue. Few days from now and they will come off very easily I suppose . There are no new discolored spots showing on the plants. Two days ago I sprayed them with systemic fungicide . Could this be from over or under watering ?? I know someone must have encountered this ...

[spaugh]

Looks fine.  Dragonfruit get all kinds of unsightly spots on them its perfectly normal.  Some of the pics look like cracked parts from damage maybe from the mail.

Just levae them alone stop worrying.  Youdont need to use systemics or anything on them.  You are going way overkill.  This plant is a weed, it doesnt need any babying.

[Plantinyum]

Looks fine.  Dragonfruit get all kinds of unsightly spots on them its perfectly normal.  Some of the pics look like cracked parts from damage maybe from the mail.

Just levae them alone stop worrying.  Youdont need to use systemics or anything on them.  You are going way overkill.  This plant is a weed, it doesnt need any babying.

I dont think so ...the yellow part is very soft and gummy ..it separates from the other parts of the plant ...this has never happened for me , its not that its just yellow , the tissue in this spot gets rejected by the plant and is dying ...

[roblack]

Maybe it is dying, but often dragon fruit loses the fleshy tissue and maintains the core stem. Plant grows and lives on.

[Plantinyum]

Maybe it is dying, but often dragon fruit loses the fleshy tissue and maintains the core stem. Plant grows and lives on.

that is happening with mine also ,the very tips of the segments that are yellowing are fine , its just very strange for me, i'm used to seeing  my plants healthy and now this get me quite disturbed.  However I will calm down and will keep u all updated on the plants