I just noticed that this problem extends to other ITRANS keyboards too; I use the Hindi Devanagari Phonetic (ITRANS) keyboard for Devanagari and Bengali Phonetic (ITRANS) for Bangla.
I can’t type #, $, %, ^, &, *, _, + in Bangla either, I get ওঁ, ₹, ࿕, ্, , ❀ . So I think this needs to be looked at a generic scale.
Another bug which I want to bring to notice is…
The inputs like .D, .Dh, .y, .k, .kh, .g, .j, .f, .n, .r, .L render ড়, ঢ়, য় (Bangla), ड़, ढ़, य़, क़, ख़, ग़, ज़, फ़, ऩ, ऱ, ऴ (Devanagari) as "letter + nuqta" although many of these letters are individual unique points in Unicode and therefore it is unnecessarily rendering two characters instead, which is a practice Unicode disapproves of.
In Bangla it renders, ড/ঢ/য + ় (U+09BC) and for Devanagari it renders ड/ढ/य/क/ख/ग/ज/फ/न/र/ळ + ़ (U+093C).
I believe this bug needs to be fixed, so that one can input the following characters as single Unicode points instead…
क़ (U+ 0958), ख़ (U+ 0959), ग़ (U+ 095A), ज़ (U+ 095B), ड़ (U+ 095C), ढ़ (U+ 095D), फ़ (U+ 095E), य़ (U+095F), ऩ (U+ 0929), ऱ (U+ 0931), ऴ (U+ 0934)
ড় (U+09DC), ঢ় (U+ 09DD), য় (U+ 09DF)