[docs] Update builder docs on last-modified times
Docker-DCO-1.1-Signed-off-by: Josh Hawn (github: jlhawn)
@@ -519,8 +519,8 @@ All new files and directories are created with a UID and GID of 0.
In the case where `<src>` is a remote file URL, the destination will
have permissions of 600. If the remote file being retrieved has an HTTP
`Last-Modified` header, the timestamp from that header will be used
-to set the `mtime` on the destination file. Then, like any other file
-processed during an `ADD`, `mtime` will be included in the determination
+to set the `mtime` on the destination file. However, like any other file
+processed during an `ADD`, `mtime` will not be included in the determination
of whether or not the file has changed and the cache should be updated.
> **Note**:
