Soggy cactus, RIP :(

[GemmaS1234]

Hi all,

Today was a really sad day as my Austrocylindropuntia subulata cultivar monstrose (as someone on here kindly identified) finally bit the dust! I had had her for years, and only noticed really today that the light coloured part of the stem was orange/yellow and was in fact soggy. It has had problems in the past with fungus in the soil, despite using the same soil with others and them not having this issue (touch wood!) , I barely water my cacti in the Summer about once a month/when they look very dry , and don't really touch them in the winter. Also not sure why some of the hairs on the cactus turned crispy-ishhh.

I have taken cuttings from the bits that were salvageable, I was just wondering why it became soggy and also on some of the limbs the hairs changed colour as shown.

I would be so grateful if someone could help me please!!!