I've reviewed your log... And I did find something disturbing... The following was reported:
175.<6>[ 1.011826] PMU: registered new PMU device of type 0
176.<4>[ 1.012021] DVFS MSG: core: dvfs_adjust_table_lmtvolt get leakage_level = 2
177.<4>[ 1.012080] adjust table freq=1800000 KHz, index=1375000 mV to index=1350000 mV
178.<4>[ 1.012149] DVFS MSG: aclk_gpu: dvfs_adjust_table_lmtvolt get leakage_level = 2
179.<4>[ 1.013063] cpufreq: delete arm freq(1608000)
180.<4>[ 1.013105] cpufreq: delete arm freq(1800000)
181.<4>[ 1.051133] rk3188 cpufreq version 2.1, suspend freq 1200 MHz
It seems during boot up, the system checks for any instability as a result of using higher voltage values to support increased CPU speeds. Your voltage leakage level is 2, mine is 0. As a result, upon booting up, your system seems to delete frequencies 1,608 Mhz & 1,800 Mhz due to stability issues and then forces to lock on 1,200 Mhz...
I will need to take a closer look at this. I have never seen anything like this before. I believe it has got to do with the ACT8846 which is built into the rockchip SOC. I'll have more on this once I do my tests.
Anyone with knowledge on this is welcome to share his input.