Ok folks, I figured it out especially as it relates to Lexus cars with the older infotainment systems. My wife and I both upgraded to iPhone 15 Pros, me the Pro Max. I started as if bluetooth might have been an issue, so with the new phones unpaired and bluetooth turned off on both phones, I directly plugged into the USB data outlet and installed Car Play that way, like it was in past wired Lexus cars. Damn, after I invoked Siri and requested a message be sent, there was no difference. After Siri began saying "what do you want to...." everything became busted and truncated. That was when I noticed the Lexus microphone icon in the upper left of the screen turning on and off. It does not know when to remain off as verbal instructions are being given to Siri. What's happening is Siri goes into an internal feedback loop! The workaround is as soon as your Siri command is verbally invoked, you hit the back arrow next to the mic icon forcing the Lexus mic to remain off or disappear. You will not hear the verbal feedback from Siri but she gets it right every time. When the send button appears, you either tap it on a touchscreen or say "send." This only affects outgoing Siri messaging, there is no problem with any incoming messages. Phone calls are not an issue because the mic remains open all the time. it's only when Siri is engaging with verbal feedback and the Lexus mic does not know what the hell iis going on. It does not affect MY 2023 NX infotainment system because that car has the newest 14" touch screen system with climate control. No mic icon ever appears. On my wife's new ES 350, that car has a bastardized hybrid head unit with a small 7' (new tech) touchscreen but... the climate control is still the older car manual push buttons. I had this issue with older Lexus models before they went wireless. Bottom line, this is a LEXUS PROBLEM, it is NOT APPLE or the current IOS. I have reported it to Lexus in the hopes this gets looked at.