We made iOS app with MfiBtPrinterConnection and TcpPrinterConnection to make connections between iOS device and Zebra mobile printer (ZQ620 and QLN320)
(https://techdocs.zebra.com/link-os/2-13/ios/content/interface_mfi_bt_pr…)

The source code is exactly the same as example above link but there is only problem when I try to print out with ZQ620 + Bluetooth 5.0 Device (iPhone SE 2nd generation, iPhone 11Pro, iPhone11) - with MfiBtPrinterConnection

No issue between (For QLN320, We have tried with LINK OS 6.2 and 6.3)
QLN320 + iPod touch 5th generation (Bluetooth 4.1)
QLN320 + iPod touch 6th generation (Bluetooth 4.1)
QLN320 + iPod touch 7th generation (Bluetooth 4.1)
QLN320 + iPhone SE 2nd generation (Bluetooth 5.0)
QLN320 + iPhone 11 Pro (Bluetooth 5.0)
QLN320 + iPhone 11 (Bluetooth 5.0)
ZQ620 + iPod touch 5th generation (Bluetooth 4.1)
ZQ620 + iPod touch 6th generation (Bluetooth 4.1)
ZQ620 + iPod touch 7th generation (Bluetooth 4.1)
and all TcpPrinterConnection printing

Only thing I added is that I am checking printer status by getCurrentStatus to check whether my printer is enabled to print out or not, like the sequence below.
MfiBtPrinterConnection -> ZebraPrinterConnection.open -> ZebraPrinterFactory.getInstance -> getCurrentStatus() -> Write -> ZebraPrinterConnection.close

There is no problem when printing successively after the first successful printing. But when I try to print again after waiting a while after printing, getCurrentStatus() throws an exception randomly. After that, the printer is paired, but the paired device cannot be found in the app.
Error Domain=ZSDK_API_ERROR_DOMAIN Code=7 "Malformed status response - unable to determine printer status" UserInfo={NSLocalizedDescription=Malformed status response - unable to determine printer status}
(connection open() and isConnected() are returning turu)

I tried to prevent exceptions using setTimeToWaitForMoreData, setMaxTimeoutForRead, delay() and etc, But there is no way to fix it.
I'm so confused because it's a problem that doesn't happen with other device combinations. I could find a similar issue like
https://developer.zebra.com/thread/35152
https://developer.zebra.com/thread/35033
https://github.com/ZebraDevs/LinkOS-iOS-Samples/issues/5
but there is no reply to solve the problem.
No issue with iOS(11,12,13,14), linkOS version, enabled BLE setting, enabled WLAN setting, Sleep setting. We have a lot of ZQ620 printers and the same issue has happened.

This problem is a problem that occurs in getting status after opening a connection. Please give me advice.

ALREADY TRIED
! U1 setvar "bluetooth.discoverable" "on"
! U1 setvar "bluetooth.authentication" "off"
! U1 setvar "bluetooth.bluetooth_pin" ""
! U1 setvar "bluetooth.afh_mode" "off"
! U1 setvar "bluetooth.afh_map" ""
! U1 setvar "wlan.enable" "off"