Intermittent assertion failure at GameClient or GameServer

[oznogon]

EmptyEpsilon inconsistently crashes when entering the server selection screen from a client:

Assertion failure at GameClient (/home/gguillotte/git/daid/SeriousProton/src/multiplayer_client.cpp:19), triggered 1 time:
  '!game_client'

Trace/breakpoint trap (core dumped)

gdb backtrace:

#0  0x0000000000474c3b in GameClient::GameClient(int, sp::io::network::Address, int) ()
#1  0x00000000005e680e in JoinServerScreen::JoinServerScreen(ServerScanner::ServerInfo const&) ()
#2  0x00000000005eb9c3 in ServerBrowserMenu::connect(ServerScanner::ServerInfo const&) ()
#3  0x00000000005eb93a in ServerBrowserMenu::connect(string) ()
#4  0x00000000005e87a4 in ServerBrowserMenu::ServerBrowserMenu(std::optional<GameClient::DisconnectReason>)::{lambda()#2}::operator()() const ()
#5  0x00000000005ed718 in void std::__invoke_impl<void, ServerBrowserMenu::ServerBrowserMenu(std::optional<GameClient::DisconnectReason>)::{lambda()#2}&>(std::__invoke_other, ServerBrowserMenu::ServerBrowserMenu(std::optional<GameClient::DisconnectReason>)::{lambda()#2}&) ()
#6  0x00000000005ec989 in std::enable_if<is_invocable_r_v<void, ServerBrowserMenu::ServerBrowserMenu(std::optional<GameClient::DisconnectReason>)::{lambda()#2}&>, void>::type std::__invoke_r<void, ServerBrowserMenu::ServerBrowserMenu(std::optional<GameClient::DisconnectReason>)::{lambda()#2}&>(ServerBrowserMenu::ServerBrowserMenu(std::optional<GameClient::DisconnectReason>)::{lambda()#2}&)
    ()
#7  0x00000000005ebf52 in std::_Function_handler<void (), ServerBrowserMenu::ServerBrowserMenu(std::optional<GameClient::DisconnectReason>)::{lambda()#2}>::_M_invoke(std::_Any_data const&) ()
#8  0x000000000056df38 in std::function<void ()>::operator()() const ()
#9  0x00000000009a7f71 in GuiButton::onMouseUp(glm::vec<2, float, (glm::qualifier)0>, long) ()
#10 0x0000000000999307 in GuiCanvas::onPointerUp(glm::vec<2, float, (glm::qualifier)0>, long) ()
#11 0x000000000049cf52 in RenderLayer::onPointerUp(glm::vec<2, float, (glm::qualifier)0>, long) ()
#12 0x000000000049cfb6 in RenderLayer::onPointerUp(glm::vec<2, float, (glm::qualifier)0>, long) ()
#13 0x000000000049cfb6 in RenderLayer::onPointerUp(glm::vec<2, float, (glm::qualifier)0>, long) ()
#14 0x0000000000499fe2 in PostProcessor::onPointerUp(glm::vec<2, float, (glm::qualifier)0>, long) ()
#15 0x0000000000499fe2 in PostProcessor::onPointerUp(glm::vec<2, float, (glm::qualifier)0>, long) ()
#16 0x00000000004d55d7 in Window::handleEvent(SDL_Event const&) ()
#17 0x000000000041538e in Engine::handleEvent(SDL_Event&) ()
#18 0x0000000000414a84 in Engine::runMainLoop() ()
#19 0x000000000056720d in main ()

Or when starting a scenario as a server:

Assertion failure at GameServer (/home/gguillotte/git/daid/SeriousProton/src/multiplayer_server.cpp:32), triggered 1 time:
  '!game_server'

Trace/breakpoint trap (core dumped)

gdb backtrace:

#0  0x0000000000483c8b in GameServer::GameServer(string, int, int) ()
#1  0x000000000057258e in EpsilonServer::EpsilonServer(int) ()
#2  0x00000000005fde7f in ServerSetupScreen::ServerSetupScreen()::{lambda()#2}::operator()() const ()
#3  0x000000000060d7fa in void std::__invoke_impl<void, ServerSetupScreen::ServerSetupScreen()::{lambda()#2}&>(std::__invoke_other, ServerSetupScreen::ServerSetupScreen()::{lambda()#2}&) ()
#4  0x000000000060c72f in std::enable_if<is_invocable_r_v<void, ServerSetupScreen::ServerSetupScreen()::{lambda()#2}&>, void>::type std::__invoke_r<void, ServerSetupScreen::ServerSetupScreen()::{lambda()#2}&>(ServerSetupScreen::ServerSetupScreen()::{lambda()#2}&) ()
#5  0x000000000060b984 in std::_Function_handler<void (), ServerSetupScreen::ServerSetupScreen()::{lambda()#2}>::_M_invoke(std::_Any_data const&) ()
#6  0x000000000056df38 in std::function<void ()>::operator()() const ()
#7  0x00000000009ab123 in GuiButton::onMouseUp(glm::vec<2, float, (glm::qualifier)0>, long) ()
#8  0x000000000099c4b9 in GuiCanvas::onPointerUp(glm::vec<2, float, (glm::qualifier)0>, long) ()
#9  0x000000000049cf52 in RenderLayer::onPointerUp(glm::vec<2, float, (glm::qualifier)0>, long) ()
#10 0x000000000049cfb6 in RenderLayer::onPointerUp(glm::vec<2, float, (glm::qualifier)0>, long) ()
#11 0x000000000049cfb6 in RenderLayer::onPointerUp(glm::vec<2, float, (glm::qualifier)0>, long) ()
#12 0x0000000000499fe2 in PostProcessor::onPointerUp(glm::vec<2, float, (glm::qualifier)0>, long) ()
#13 0x0000000000499fe2 in PostProcessor::onPointerUp(glm::vec<2, float, (glm::qualifier)0>, long) ()
#14 0x00000000004d55d7 in Window::handleEvent(SDL_Event const&) ()
#15 0x000000000041538e in Engine::handleEvent(SDL_Event&) ()
#16 0x0000000000414a84 in Engine::runMainLoop() ()
#17 0x000000000056720d in main ()