OT: Urdu, like Arabic/Persian, is written with an alphabet where letters can change shape based on whether they are at the start, middle or end of a "word" [1]. I say "word" because some letters don't have a middle form, so each actual word is broken into a sequence of composite-letter-shapes, where each composite shape start with such a no-middle-form letter.

A problem arises when one wants to write a compound word, which the last letter for the first word and the first letter of the second word must not be joined. To achieve this, the unicode standard has U+200C ZERO WIDTH NON-JOINER character, which should be used in such compound words [2]. The standard SPACE character should not be used because it will create a physical space, while U+200C will create a break with no space.

However, typically Urdu keyboards don't have this character in them, so everyone ends up either using SPACE or just joining the words.

[1] https://en.wikipedia.org/wiki/Urdu_alphabet

[2] https://en.wikipedia.org/wiki/Zero-width_non-joiner