The same thing is happening to me, but in my case, on the ILS W 32R approach to LEMD.
In this case, the ILS information appears correctly in the NAV section of the MCDU, including both the frequency (109.1), the identifier (MBB), and the heading (323 degrees). In the ND, the frequency and ILS indication appear in magenta, but the magenta diamonds for LOC and GS are never present, nor is the DME distance. In other words, everything is correct, but the signal is not being received and, therefore, the signal is not being intercepted.
I must say that I have tried manually entering the data, including the frequency, identification, and heading. Nothing works.
I must also say that I have detected this, at least in my case, since version 1.0.3. When version 1.0.4 came out, I deleted WASM, updated the Navigraph data with my subscription... I did a test flight and everything worked on that same ILS, but today, after I just arrived on a new flight, it's down again. I haven't done anything different or updated anything from the flight I took yesterday, where it did work.
Finally, I did the test with it and that ILS works perfectly with other aircraft, like your A300 and the Fenix A320. I fly a lot out of Madrid for Iberia Virtual, and it's a widely used approach daily with all of these aircraft, and none of them show errors except for the A350, so it's not a scenario issue.
I've also seen with other colleagues that it's very random, meaning it works for some, and not for others. I don't know which version they fly.
In my case: latest version of MSFS24, W11, updated Navigraph, and aircraft version with the latest update 1.0.4.
If you have any additional questions or need additional screenshots, please feel free to contact me.
P.S. I'm sending you some screenshots (number 1, 2) where you can see what I'm explaining and where it doesn't work correctly.
I'm also sending you a screenshot of the test I performed after recently deleting WASM and installing version 1.0.4, where you can see that it did work and received a signal at over 25nm.