Please check the iOS versions on each device again
Learn about Available trusted root certificates for Apple operating systems - Apple Support
This is part of iOS updates which can be clearly seen below
iPhone 12 Pro iOS 16.3 Trust Store Version: 2022070700 and Trust Asset Version 20
iPhone 8 iOS 16.2 Trust Store Version: 2022070700 and Trust Asset Version 20
iPad Pro 9.7" iOS 16.2 Trust Store Version: 2022070700 and Trust Asset Version 20
iPhone 13 Pro iOS 16.2 Trust Store Version: 2022070700 and Trust Asset Version 20
I may have missed Asset Version 19
All my devices, iPhone 8 (iOS 16.0), iPhone 12 Pro (iOS 16.1.1) & iPhone 13 Pro on iOS 16.1.1 also iPad Pro on iPadOS 16.1 are with Trust Store Version: 2022070700 and Trust Asset Version 18
iPhone SE (1st Gen) iOS 15.7 2022031500 and Trust Asset Version 18
Earlier, iPhone 8, SE (1st Gen), iPhone 12 Pro & iPhone 13 Pro on iOS 15.6.1 also iPad Pro on iPadOS 15.6.1 all are with Trust Store Version: 2022031500 and Trust Asset Version 17
iPhone 6 iOS 12.5.5 Trust Store Version 2018121000, Does not have Trust Asset Version
After updated my iPhone 6 to iOS 12.5.6 it still has Trust Store Version 2018121000, Does not have Trust Asset Version
There is an old discussion thread on Trust Asset Versions that may help you understand --> Trust asset version 11. - Apple Community