Could not type diacritics chars in Atom on Ubuntu

I’m using Atom 1.50.0 x64 on Ubuntu. When I try to enter a diacritic char, nothings happens (no char is shown for this input). For example, to enter the “ã” simbol I type the “~” (tilde) simbol and the letter “a”. As you can see, it is working for other programs, but not while using the Atom. This happens for all diacritics (áéíóú…)

I’m using Ubuntu 20.04 64-bits. My keyboard is configured as US-International with dead keys, the keyboard input method system is XIM. The following is my regional configuration:
LANG=en_US.UTF-8
LANGUAGE=
LC_CTYPE=pt_BR.UTF-8
LC_NUMERIC=pt_BR.UTF-8
LC_TIME=pt_BR.UTF-8
LC_COLLATE=“en_US.UTF-8”
LC_MONETARY=pt_BR.UTF-8
LC_MESSAGES=“en_US.UTF-8”
LC_PAPER=pt_BR.UTF-8
LC_NAME=pt_BR.UTF-8
LC_ADDRESS=pt_BR.UTF-8
LC_TELEPHONE=pt_BR.UTF-8
LC_MEASUREMENT=pt_BR.UTF-8
LC_IDENTIFICATION=pt_BR.UTF-8
LC_ALL=

Can you help me in this issue?