Yes it seems to be normal for this device. That's a pity. This is the reaseon why i don't use the device anymore, because of the high battery drain in standby.
My Nexus 9 has a 6000mA battery and lasts more than a week in standby, although it has a (bigger screen and) more powerful CPU/GPU.
The Hi8 Pro has a 4000mA battery, (a smaller screen,) a less powerfull CPU/GPU, but still it lasts only 1,5 to 2 days in standby. The ROM and the BIOS needs more optimizing.
I understand that when i use heavy load Apps that i have to charge the device more often, but i don't understand why i have to charge that device that often when only in standby.
The problem that i see is that Chuwi and other companies only buy the technology, build cheap devices and sell them. They do not have the knowledge or do not take the time to refine their products.
They use standard software parts and standard drivers. They rely on the CPU and SOC vendors for the drivers. You can say, they (Chuwi and others) are more ROM cookers than ROM developers.
It might not be Chuwi's fault, it might be Intel's fault. It also might be that these companies do not buy the proper licences, so they don't get the proper support from the vendors.
That's why bigger companies, like Samsung, Huawei and Sony have better and more frequent updates for their devices. They have better support from the vendors and the leverage for speeding up fixing vendor specific problems. For us customers the problemis , that from our perspective Chuwi is the vendor.
Still, i hope that someday Chuwi has an optimized ROM for proper use. But, more likely i will sell this device. As a consequence of above said things, i won't buy anymore devices from Chuwi, Umi, Ulefone, Teclast, etc.
Instead i will buy a device with better software and support from Samsung or Huawei.
Only good device specs (like tha Hi8 Pro) do not make a good device. For a succesful business you also must have good software and support.