NextDNS crashes every 30 seconds on AsusWrt Merlin AC86U

On my AC86U Router I get every 30 seconds the following log nextdns Tainted:

kernel: Code: e59d3014 e59d4018 e59d501c ef000000 (e59f6038)

kernel: CPU: 0 PID: 1464 Comm: nextdns Tainted: P          O    4.1.27 #2

kernel: Hardware name: Broadcom-v8A (DT)

kernel: task: ffffffc019226040 ti: ffffffc016518000 task.ti: ffffffc016518000

kernel: PC is at 0x15f60

kernel: LR is at 0x15f24

kernel: pc : [<0000000000015f60>] lr : [<0000000000015f24>] pstate: 60000010

kernel: sp : 0000000000d1153c

kernel: x12: 0000000000c90383

kernel: x11: 0000000000000007 x10: 0000000000dc2a28

kernel: x9 : 0000000000000000 x8 : 0000000000000007

kernel: x7 : 00000000000001b7 x6 : 0000000000dc2a70

kernel: x5 : 0000000000000000 x4 : 0000000000000000

kernel: x3 : 0000000000000200 x2 : 0000000000000001

kernel: x1 : 0000000000c90380 x0 : 00000000ffffff9c

AC86U runs on the latest Asuswrt Merlin firmware (386.13_2). 
NextDns is updated to the latest version (v1.43.5).

I have formatted my USB (ext4) and installed nextdns again. But the error messages are still showing up.

On my AX86U Router where NextDns CLi is also installed I don't get these logs.

Any solutions to this ?