ESP8266 with NodeMCU AP net mask 255.255.255.240 - esp8266

Question

Is there any issue in NodeMCU or ESP8266, which does not allow us to have 255.255.255.240 as netmask for AP? I configured net mask as 255.255.255.240 and when I do
if(wifi.getmode() == wifi.SOFTAP or wifi.getmode() == wifi.STATIONAP ) then
ip, nm, gw = wifi.ap.getip()
print("AP IP Info ip nm gw:",ip, nm, gw)
end
it prints properly like
AP IP Info ip nm gw: 10.100.0.1 255.255.255.240 10.100.0.1
but, ifconfig of my computer (and other ESP8266) connected to it shows netmask as 255.255.255.0.
Sample ifconfig from my laptop
wlp0s20u4u2: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 10.100.0.2 netmask 255.255.255.0 broadcast 10.100.0.255
inet6 fe80::225:22ff:fe4d:2691 prefixlen 64 scopeid 0x20<link>
ether xx:xx:xx:xx:xx:xx txqueuelen 1000 (Ethernet)
RX packets 121518 bytes 77302112 (73.7 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 117446 bytes 16933718 (16.1 MiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
Any idea or fix?
Sample code
apIPCfg={}
apCfg={}
apCfg.ssid="abcdefgh"
apCfg.pwd="abcdefgh12345678"
apCfg.auth=AUTH_WPA2_PSK
apIPCfg.ip='10.100.0.1'
apIPCfg.netmask='255.255.255.240'
apIPCfg.gateway='10.100.0.1'
wifi.setmode(wifi.STATIONAP)
wifi.ap.setip(apIPCfg)
wifi.ap.config(apCfg)
Build details
NodeMCU custom build by frightanic.com
branch: dev
commit: 7d576efed94092916e1a84bccba6319d62b9dedf
SSL: true
modules: adc,bit,cjson,coap,crypto,encoder,enduser_setup,file,gpio,http,mqtt,net,node,struct,tmr,uart,wifi
build built on: 2016-04-08 07:08
powered by Lua 5.1.4 on SDK 1.5.1(e67da894)
lua: cannot open init.lua
> apIPCfg={}
> apCfg={}
> apCfg.ssid="abcdefgh"
> apCfg.pwd="abcdefgh12345678"
> apCfg.auth=AUTH_WPA2_PSK
> apIPCfg.ip='10.100.0.1'
> apIPCfg.netmask='255.255.255.240'
> apIPCfg.gateway='10.100.0.1'
> wifi.setmode(wifi.STATIONAP)
> wifi.ap.setip(apIPCfg)
> wifi.ap.config(apCfg)
> ip, nm, gw = wifi.ap.getip()
> print("AP IP Info ip nm gw:",ip, nm, gw)
AP IP Info ip nm gw: 10.100.0.1 255.255.255.240 10.100.0.1
>