The reality of caps is likely to not follow ltspice, as we all know, but I was thinking that the cap may be causing the issue. Even compounded with temperature derating.
What's the AC rating of the cap in use? The DC rating is often specified, but for example WIMA caps may be 640Vdc but are rated at 400Vac. Also what is the voltage differece across the cap? If the cap isn't large enough to supply the required current, and then driven from the driver side to create it you'd see attenuation.
What's the AC rating of the cap in use? The DC rating is often specified, but for example WIMA caps may be 640Vdc but are rated at 400Vac. Also what is the voltage differece across the cap? If the cap isn't large enough to supply the required current, and then driven from the driver side to create it you'd see attenuation.