Is it intended that transfiguration is replacing affixes on your gear literally ruining it, because it’s not modifiable afterwards?
Yes, it’s one of 5 possible outcomes:
- Indestructible
- Upgrade to Greater Affix
- Bonus Transfiguration affix (full afix pool)
- Replace existing affix with Transfiguration Affix
- Bonus item quality
That’s why it’s wise to have always a duplicate before transfiguring.
Unless you use a Entropic Prism, then it’s:
- Bonus Transfiguration affix (partial affix pool)
- Bonus item quality
This isn’t a bug. If you’re just curious to how something works, it’s best to post the question in the General Discussion forum first.