Aircraft lift-induced condensation (condensation caused because the thing is, like, screaming into the sky on a moist day):
To really see if the sound barrier has been broken, full motion video must be observed. A still pic won’t let you know if Mach 1 has been reached or exceeded.
As an aircraft passes through trans-sonic flight the center of pressure moves aft and a discernable nose down movement can be observed. This is known as Mach Tuck.
This tuck is often attributed to the early losses of Lear 23 business aircraft and lead to the FAA requiring a two pilot cockpit rule on sweapt wing aircraft and the ‘barber pole’ on the airspeed indicator.
I can recall times when a Tomcat leaving NAS Alameda would literally disappear from view over the bay in its own cloud on a foggy morning.