Missing JSServe.js in Firefox snap

On loading the GUI in Firefox, the following "warning" message occasionally appears in the repl:

┌ Warning: error in websocket handler!
└ @ JSServe /usr/local/share/julia/packages/JSServe/kIK9q/src/http.jl:84
Key does not map to a local path (is not registered via `register_local_file`): /assetserver/0ca72be5e6b8b238fc78239e6ac7510fa8410203-JSServe.js line 162 > Function
Stacktrace:
  [1] error(s::String)
    @ Base ./error.jl:35
  [2] assetserver_to_localfile
    @ /usr/local/share/julia/packages/JSServe/kIK9q/src/dependencies.jl:22 [inlined]
  [3] replace_url(match_str::SubString{String})
    @ JSServe /usr/local/share/julia/packages/JSServe/kIK9q/src/http.jl:48
  [4] _replace(io::IOBuffer, repl::typeof(JSServe.replace_url), str::String, r::UnitRange{Int64}, pattern::Base.RegexAndMatchData)
    @ Base ./strings/util.jl:665
  [5] replace(str::String, pat_repl::Pair{Regex, typeof(JSServe.replace_url)}; count::Int64)
    @ Base ./strings/util.jl:706
  [6] #replace#451
    @ ./strings/util.jl:775 [inlined]
  [7] replace(s::SubString{String}, pat_f::Pair{Regex, typeof(JSServe.replace_url)})
    @ Base ./strings/util.jl:775
  [8] JSServe.JSException(js_data::Dict{Any, Any})
    @ JSServe /usr/local/share/julia/packages/JSServe/kIK9q/src/types.jl:150
  [9] handle_ws_message(session::JSServe.Session, message::Vector{UInt8})
    @ JSServe /usr/local/share/julia/packages/JSServe/kIK9q/src/http.jl:67
 [10] handle_ws_connection(application::JSServe.Server, session::JSServe.Session, websocket::WebSockets.WebSocket{Sockets.TCPSocket})
    @ JSServe /usr/local/share/julia/packages/JSServe/kIK9q/src/http.jl:99
 [11] websocket_handler(context::NamedTuple{(:routes, :application, :request, :match), Tuple{JSServe.Routes, JSServe.Server, HTTP.Messages.Request, RegexMatch}}, websocket::WebSockets.WebSocket{Sockets.TCPSocket})
    @ JSServe /usr/local/share/julia/packages/JSServe/kIK9q/src/http.jl:130
 [12] apply_handler(::Function, ::NamedTuple{(:routes, :application, :request, :match), Tuple{JSServe.Routes, JSServe.Server, HTTP.Messages.Request, RegexMatch}}, ::WebSockets.WebSocket{Sockets.TCPSocket})
    @ JSServe /usr/local/share/julia/packages/JSServe/kIK9q/src/server.jl:38
 [13] delegate(routes::JSServe.Routes, application::JSServe.Server, request::HTTP.Messages.Request, args::WebSockets.WebSocket{Sockets.TCPSocket})
    @ JSServe /usr/local/share/julia/packages/JSServe/kIK9q/src/server.jl:64
 [14] #14
    @ /usr/local/share/julia/packages/JSServe/kIK9q/src/server.jl:171 [inlined]
 [15] upgrade(f::JSServe.var"#14#16"{JSServe.Server}, stream::HTTP.Streams.Stream{HTTP.Messages.Request, HTTP.ConnectionPool.Transaction{Sockets.TCPSocket}})
    @ WebSockets /usr/local/share/julia/packages/WebSockets/QcswW/src/HTTP.jl:201
 [16] stream_handler(application::JSServe.Server, stream::HTTP.Streams.Stream{HTTP.Messages.Request, HTTP.ConnectionPool.Transaction{Sockets.TCPSocket}})
    @ JSServe /usr/local/share/julia/packages/JSServe/kIK9q/src/server.jl:170
 [17] #invokelatest#2
    @ ./essentials.jl:729 [inlined]
 [18] invokelatest
    @ ./essentials.jl:726 [inlined]
 [19] #26
    @ /usr/local/share/julia/packages/JSServe/kIK9q/src/server.jl:302 [inlined]
 [20] macro expansion
    @ /usr/local/share/julia/packages/HTTP/aTjcj/src/Servers.jl:415 [inlined]
 [21] (::HTTP.Servers.var"#13#14"{JSServe.var"#26#28"{JSServe.Server}, HTTP.ConnectionPool.Transaction{Sockets.TCPSocket}, HTTP.Servers.Server{Nothing, Sockets.TCPServer}, HTTP.Streams.Stream{HTTP.Messages.Request, HTTP.ConnectionPool.Transaction{Sockets.TCPSocket}}})()

This happens in Firefox 111.0.1, snap version. The GUI properly opens in Brave browser. This may be a snap-specific bug again. To be confirmed...

EDIT: Confirmed! The Flatpak version does not have the issue. The AppArmor config for snaps may be too restrictive.