NEWS about back-transformation of "rclr" standardization

Author: jarioksa

NEWS.md

@@ -53,6 +53,10 @@
   names of imputed matrix. Issue
   [#759](https://github.com/vegandevs/vegan/issues/759).
 
+  Back-transformation of `"rclr"` failed with `decobackstand`.
+  Back-transformation cannot be done with imputed matrix, and without
+  imputed matrix original zeros were returned as `NA`.
+
 ## Defunct
 
 * Lattice functions `ordicloud`, `ordiresids`and `ordisplom` are