Writer 5.4.6.2: Bengali language paragraph alignment isn't properly Justified

INTRODUCTION

I’m using LibreOffice 5.4.6.2 in Ubuntu 17.10 operating system. Both of my Locale setting and the Complex text layout setting are set to Bengali (Bangladesh). I use IBus m17n as the language input method to write Bangla/Bengali texts.

THE PROBLEM

When I use the Format - Paragraph - Alignment tab - Option - Justified command, the Bengali language paragraphs in my .odt documents do not get justified properly. The right side of the alignment gets unevenly justified. Moreover, the spaces between the words — and the spaces between the words and the punctuation marks — are unevenly distributed. That is to say, there are false spaces appearing randomly here and there in the paragraphs. (Please see the screenshot file attached herewith.)

If I try to delete such a false space by putting the cursor to the right side of the “space” and hit the Backspace Key, the “space” doesn’t delete; it actually deletes the immediate next character to the left of the cursor.

Please tell me how to fix the problem.

TWO CLUES

Clue One: When I convert the same Bengali language paragraphs to any of English language fonts like Liberation Serif the justification alignment and spaces become absolutely perfect.

Clue Two: English language paragraphs in the same document (even if they are converted to some Bengali language font like Lohit Bengali) shows no such trouble. They are just okay.

THANK YOU VERY MUCH.

(edit: activated screenshot)

There are a few bugs lately which deal with character width.
This one has a number of other language-specific spacing bugs pointing to it as “same issue”.
Bug 105913 - Calculating character widths is broken for ligatures in 5.3

This is supposed to be fixed in the latest daily builds.
So if you can test with that it may be your issue will be resolved when 6.1.0 is released.

Thank you very much.

Could you please tell me how to check/get/test the latest daily build?

And when is the 6.1.0 release expected?

I’m gonna install 18.04 which include LibreOffice 6. Hope that solve my problem. Thank you.

I’ve now upgraded to Ubuntu 18.04 with LibreOffice 6.0. But the problem still persists here. What to do? At a loss. Please suggest something. Thank you.

May I use LibreOffice Writer 5.1.0.3 in Ubuntu 18.04?

Sorry for the late reply. I never get any notifications from this thing.
Daily builds can be downloaded here:
https://dev-builds.libreoffice.org/daily/libreoffice-6-0/

If you give that a try, please come back and report your results.