Extremely slow FileVault boot on Catalina

Using Catalina developer beta 7, but the issue has existed since the first beta.

Using FileVault booted to the Preboot volume, boot will hang on the Apple logo for 1 minute and 45 seconds to before the login window appears. Verbose mode doesn't work(?) during this process so I have no idea what's going on. There is no disk activity according to PC indicator light while Apple logo is shown. Is there any way to debug this? Does anyone else using FileVault on Catalina experience this?

Clover 5070 Gigabyte Z170XP-SLI 7700K Radeon 590 850 EVO SSD IntelMausiEthernet.kext (v.2.5.0d0) USBInjectAll.kext (v.0.7.1) HDMIAudio.kext (v.1.1) dAGPM.kext (v.1.0.0) Lilu.kext (v.1.3.8) VirtualSMC.kext (v.1.0.7) SMCSuperIO.kext (v.1.0.7) SMCProcessor.kext (v.1.0.7) WhateverGreen.kext (v.1.3.1) AppleALC.kext (v.1.4.1)