MQTT Devices randomly not responding to cmnd topic

Hi all,
i have all my home running Shelly with Espurna and it was working great until this days.
The problem that I am experiencing is that randomly some devices do not respond to the command via mqtt until they are restarted. If I operate the relay directly from the web page, the state topic is correctly sent by espurna. MQTT is always connected even when the problem occurs and the wifi have strong signal.

Device information
Manufacture rALLTERCO
Device SHELLY1
Chip ID 2C8A20
Wifi MAC 3C:71:BF:2C:8A:20
SDK version1.5.3(aec24ac9)
Core version 2.3.0
Firmware name ESPURNA
Firmware version 1.13.3
Firmware revisione 2641b9
Firmware build date2018-10-08 17:54:44
Firmware size 463200
bytesFree space 581632 bytes