There is no composition rule for \u09F0 (ৰ) and \u09FE (৾) in emacs,
therefore they are not rendered properly.
Steps to reproduce:
1. emacs -Q
2. Type:
     ৰাম কৰ্ম ৰূপ
     লা৾নু না৾

The following patch will fix the problem:

diff --git a/lisp/language/indian.el b/lisp/language/indian.el
index b240403b0a..b6fcdbb348 100644
--- a/lisp/language/indian.el
+++ b/lisp/language/indian.el
@@ -194,13 +194,14 @@ bengali-composable-pattern
  '(("a" . "\u0981") ; SIGN CANDRABINDU
    ("A" . "[\u0982\u0983]") ; SIGN ANUSVARA .. VISARGA
    ("V" . "[\u0985-\u0994\u09E0\u09E1]") ; independent vowel
-   ("C" . "[\u0995-\u09B9\u09DC-\u09DF\u09F1]") ; consonant
+   ("C" . "[\u0995-\u09B9\u09DC-\u09DF\u09F0\u09F1]") ; consonant
    ("B" . "[\u09AC\u09AF\u09B0\u09F0]") ; BA, YA, RA
    ("R" . "[\u09B0\u09F0]") ; RA
    ("n" . "\u09BC") ; NUKTA
    ("v" . "[\u09BE-\u09CC\u09D7\u09E2\u09E3]") ; vowel sign
    ("H" . "\u09CD") ; HALANT
    ("T" . "\u09CE") ; KHANDA TA
+           ("S" . "\u09FE") ; SANDHI MARK
    ("N" . "\u200C") ; ZWNJ
    ("J" . "\u200D") ; ZWJ
    ("X" . "[\u0980-\u09FF]")))) ; all coverage
@@ -209,7 +210,7 @@ bengali-composable-pattern
       ;; syllables with an independent vowel, or
       "\\(?:RH\\)?Vn?\\(?:J?HB\\)?v*n?a?A?\\|"
       ;; consonant-based syllables, or
-      "Cn?\\(?:J?HJ?Cn?\\)*\\(?:H[NJ]?\\|v*[NJ]?v?a?A?\\)\\|"
+      "Cn?\\(?:J?HJ?Cn?\\)*\\(?:H[NJ]?\\|v*[NJ]?v?a?A?S?\\)\\|"
       ;; another syllables with an independent vowel, or
       "\\(?:RH\\)?T\\|"
       ;; special consonant form, or