NEWS entry

Author: aitap

NEWS.md

@@ -18,6 +18,8 @@
 
 5. `as.data.table()` on `x` avoids an infinite loop if the output of the corresponding `as.data.frame()` method has the same class as the input, [#6874](https://github.com/Rdatatable/data.table/issues/6874). Concretely, we had `class(x) = c('foo', 'data.frame')` and `class(as.data.frame(x)) = c('foo', 'data.frame')`, so `as.data.frame.foo` wound up getting called repeatedly. Thanks @matschmitz for the report and @ben-schwen for the fix.
 
+6. By-reference sub-assignments to factor columns now match the levels in UTF-8, preventing their duplication when the same level exists in different encodings, [#6886](https://github.com/Rdatatable/data.table/issues/6886). Thanks @iagogv3 for the report and @aitap for the fix.
+
 ## NOTES
 
 1. Continued work to remove non-API C functions, [#6180](https://github.com/Rdatatable/data.table/issues/6180). Thanks Ivan Krylov for the PRs and for writing a clear and concise guide about the R API: https://aitap.codeberg.page/R-api/.