Brush tool Assertion failed Core Dump crash

[orbitalmartian8]

Describe the bug
On opening a new sprite in Dotto, I select the brush tool, this causes the below error and core dump.

/usr/include/c++/16.1.1/bits/stl_vector.h:1253: std::vector<_Tp, _Alloc>::reference std::vector<_Tp, _Alloc>::operator[](size_type) [with _Tp = unsigned char; _Alloc = std::allocator<unsigned char>; reference = unsigned char&; size_type = long unsigned int]: Assertion '__n < this->size()' failed.
Aborted                    (core dumped) ./dotto

To Reproduce
Steps to reproduce the bug:

1. New file
2. Select brush tool

Expected behavior
I would expect the brush tool to become functional and be able to draw, without crashing.

Device Information (please complete the following information):

• Device: Lenovo IdeaPad 110
• OS and Version: Arch Linux