ICMP reply to android getting lost !

[doremifajb]

Hello! I have samsung galaxy A3 (2017) with android 8.0.0.
I have been using Terminal Emulator to ping some devices on my network. But since it's a bit complicated to type ping -c5 192.168.1.xx so that ping wont go forever, I decided to install a keyboard with Ctrl key, so that I can just Ctrl-C to end it.

However, after that, somehow I can't ping anymore. I logged onto my router from my laptop and ran tcpdump while I type ping on android. I see that ping is actually working:

14:33:39.393866 IP 192.168.1.236 > 192.168.1.1: ICMP echo request, id 4, seq 3, length 64
14:33:39.394147 IP 192.168.1.1 > 192.168.1.236: ICMP echo reply, id 4, seq 3, length 64
14:33:40.387389 IP 192.168.1.236 > 192.168.1.1: ICMP echo request, id 4, seq 4, length 64
14:33:40.387854 IP 192.168.1.1 > 192.168.1.236: ICMP echo reply, id 4, seq 4, length 64

But somehow ICMP reply is not reaching to my android: on the Terminal it doesn't show anything. I also tried to ping with juiceSSH, but the same thing. I also restarted the device twice, but didn't work.

Could someone please help me figuring out what's going on?