Here is a bash/GDB script to fix it (tested on GNU/Linux only):

```
#!/bin/bash

gdb /usr/bin/telegram-desktop << EOF
tbreak _ZN3App9initMediaEv
commands
    set {char}_ZN3App9msgRadiusEv=0xB8
    set {int}(_ZN3App9msgRadiusEv+1)=3
    set {char}(_ZN3App9msgRadiusEv+5)=0xC3

    set {char}_Z25replaceStringWithEntitiesRK13QLatin1String5QCharR7QStringP5QListI12EntityInTextEb = 0xC3

    set {char}(_ZNK5Image10pixCircledEii+0) = 0x89
    set {char}(_ZNK5Image10pixCircledEii+1) = 0xD1
    set {char}(_ZNK5Image10pixCircledEii+2) = 0x89
    set {char}(_ZNK5Image10pixCircledEii+3) = 0xF2
    set {char}(_ZNK5Image10pixCircledEii+4) = 0xBE
    set {int}(_ZNK5Image10pixCircledEii+5) = 0x02
    set {char}(_ZNK5Image10pixCircledEii+9) = 0xE9
    set {int}(_ZNK5Image10pixCircledEii+10) = (_ZNK5Image10pixRoundedE16ImageRoundRadiusii) - (_ZNK5Image10pixCircledEii + 14)
end
run
detach
quit
EOF
```

Just run it instead of the usual Telegram binary and you're set.

This replaces the start of `App::msgRadius` with

    mov $0x3, %eax
    retq

In C++, that is `return 3`;

Explanation: `0xB8` means `mov` a number to `%eax`, `3` is the border radius, and `0xC3` is `retq`.
The first instruction in `replaceStringWithEntities` gets replacemed by a `retq`, bypassing it.