[Bug] Layer gets stuck on LT(1,KC_Z)

[neocsr]

In recent firmware builds, LT(1, KC_Z) gets stuck in layer 1 instead of reverting back to layer 0 when releasing the key KC_Z. Using the same json configuration file that was working fine in early January, now it generates a binary with this behavior. I tried both, a remote build with QMK Configurator and a local build using Docker. The other LT commands work as expected. For example LT(2,KC_A) is working fine.

Summary

After releasing KC_Z, layer 1 remains active.

System Information

• Keyboard: hotdox
• Operating system: macOS Catalina
• AVR GCC version: avr-gcc (GCC) 5.4.0
• ARM GCC version: arm-none-eabi-gcc (GNU Tools for ARM Embedded Processors 6-2017-q2-update) 6.3.1 20170620 (release) [ARM/embedded-6-branch revision 249437]
• QMK Firmware version: 0.8.101

Additional Context

• JSON file used in QMK Configurator: hotdox.json
• Keymap file: keymap.c

Flash output:

*** DFU device connected
*** Attempting to flash, please don't remove device
>>> dfu-programmer atmega32u4 erase --force
    Erasing flash...  Success
    Checking memory from 0x0 to 0x6FFF...  Empty.
>>> dfu-programmer atmega32u4 flash /Users/user/qmk_firmware/hotdox.hex
    Checking memory from 0x0 to 0x597F...  Empty.
    0%                            100%  Programming 0x5980 bytes...
    [>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>]  Success
    0%                            100%  Reading 0x7000 bytes...
    [>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>]  Success
    Validating...  Success
    0x5980 bytes written into 0x7000 bytes memory (79.91%).
>>> dfu-programmer atmega32u4 reset
    
*** DFU device disconnected
*** Z.P.Z.O. - HotDox connected -- FEED:E11D

[zvecr]

Same issue as #8600, see that issue for KC_TRANS workarounds.

[neocsr]

Tested with latest commits 927b4fe4c and 68edb1910 from https://github.com/qmk/qmk_firmware/pull/8693/commits and the issue is fixed.