Emoji reactions with identical visual results are not grouped due to unnecessary VS16s

[hcsch]

Steps to reproduce

1. Start in any matrix room with existing messages
2. Click the react button on an existing message
3. Select the thumbs-up button
4. Observe a thumbs-up emoji reaction appearing
5. Use a different client (not known to me) which generates fully-qualified emoji without unnecessary VS16s to add another thumbs-up to the same message
6. Observe two separate thumbs-up reactions that don't get grouped

Outcome

What did you expect?

Both thumbs-up reactions get grouped together, if they represent the same grapheme (i.e. both have the same visual representation), i.e. if an emoji without a text-representation has a superfluous VS16, it is grouped with the same emoji without.

Element should perhaps not generate unnecessary variation selectors and should maybe normalise emoji to their minimal representation that is still fully-qualified for reactions. This should probably still account for explicitly text-mode emoji (unclear if unqualified, clear if followed by VS15/U+FE0E), if those are intended to be supported.

What happened instead?

The visually identical reactions were grouped/counted separately.

Element generated U+1F44D U+FE0F (left in the image), while another client generated U+1F44D (right in the image), which according to https://unicode.org/Public/emoji/latest/emoji-test.txt is already fully-qualified and hence needs no VS16 (U+FE0F) to my knowledge.

Operating system

NixOS 24.05 (nixos-unstable)

Application version

Element version: 1.11.63 Crypto version: Rust SDK 0.7.0 (b1918e9), Vodozemac 0.5.1

How did you install the app?

Via NixOS package management

Homeserver

matrix.org

Will you send logs?

No

[hcsch]

The Element Android Emoji picker seems to generate a thumbs-up without VS16

[t3chguy]

This is as per the spec.

https://spec.matrix.org/v1.10/client-server-api/#mreaction

If this is an emoji, it should include the unicode emoji presentation selector (\uFE0F) for codepoints which allow it (see the emoji variation sequences list).