The bug is not reproducible everytime, but I experienced it on different machines.
While the computer is on battery, Plasma should suspend the machine when the user closes the screen lid. Instead it locked the screen.

# evemu-record 
Available devices:
/dev/input/event0:      Lid Switch
/dev/input/event1:      Sleep Button
/dev/input/event2:      Power Button
/dev/input/event3:      AT Translated Set 2 keyboard
/dev/input/event4:      SynPS/2 Synaptics TouchPad
/dev/input/event5:      Video Bus
/dev/input/event6:      TPPS/2 IBM TrackPoint
/dev/input/event7:      ThinkPad Extra Buttons
/dev/input/event8:      HDA Intel PCH Mic
/dev/input/event9:      HDA Intel PCH Dock Mic
/dev/input/event10:     HDA Intel PCH Dock Headphone
/dev/input/event11:     HDA Intel PCH Headphone
/dev/input/event12:     HDA Intel PCH HDMI/DP,pcm=3
/dev/input/event13:     HDA Intel PCH HDMI/DP,pcm=7
/dev/input/event14:     HDA Intel PCH HDMI/DP,pcm=8
Select the device event number [0-14]: 0
# EVEMU 1.3
# Kernel: 4.9.6-200.fc25.x86_64
# DMI: dmi:bvnLENOVO:bvr8DET56WW(1.26):bd12/01/2011:svnLENOVO:pn4290Y11:pvrThinkPadX220:rvnLENOVO:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:
# Input device name: "Lid Switch"
# Input device ID: bus 0x19 vendor 0000 product 0x05 version 0000
# Supported events:
#   Event type 0 (EV_SYN)
#     Event code 0 (SYN_REPORT)
#     Event code 1 (SYN_CONFIG)
#     Event code 2 (SYN_MT_REPORT)
#     Event code 3 (SYN_DROPPED)
#     Event code 4 ((null))
#     Event code 5 ((null))
#     Event code 6 ((null))
#     Event code 7 ((null))
#     Event code 8 ((null))
#     Event code 9 ((null))
#     Event code 10 ((null))
#     Event code 11 ((null))
#     Event code 12 ((null))
#     Event code 13 ((null))
#     Event code 14 ((null))
#   Event type 5 (EV_SW)
#     Event code 0 (SW_LID)
#        State 0
# Properties:
N: Lid Switch
I: 0019 0000 0005 0000
P: 00 00 00 00 00 00 00 00
B: 00 0b 00 00 00 00 00 00 00
B: 01 00 00 00 00 00 00 00 00
B: 01 00 00 00 00 00 00 00 00
B: 01 00 00 00 00 00 00 00 00
B: 01 00 00 00 00 00 00 00 00
B: 01 00 00 00 00 00 00 00 00
B: 01 00 00 00 00 00 00 00 00
B: 01 00 00 00 00 00 00 00 00
B: 01 00 00 00 00 00 00 00 00
B: 01 00 00 00 00 00 00 00 00
B: 01 00 00 00 00 00 00 00 00
B: 01 00 00 00 00 00 00 00 00
B: 01 00 00 00 00 00 00 00 00
B: 02 00 00 00 00 00 00 00 00
B: 03 00 00 00 00 00 00 00 00
B: 04 00 00 00 00 00 00 00 00
B: 05 01 00 00 00 00 00 00 00
B: 11 00 00 00 00 00 00 00 00
B: 12 00 00 00 00 00 00 00 00
B: 14 00 00 00 00 00 00 00 00
B: 15 00 00 00 00 00 00 00 00
B: 15 00 00 00 00 00 00 00 00
################################
#      Waiting for events      #
################################
E: 0.000001 0005 0000 0001      # EV_SW / SW_LID               1
E: 0.000001 0000 0000 0000      # ------------ SYN_REPORT (0) ---------- +0ms
E: 2.724497 0005 0000 0000      # EV_SW / SW_LID               0
E: 2.724497 0000 0000 0000      # ------------ SYN_REPORT (0) ---------- +2724ms
E: 12.426042 0005 0000 0001     # EV_SW / SW_LID               1
E: 12.426042 0000 0000 0000     # ------------ SYN_REPORT (0) ---------- +9702ms
E: 13.526538 0005 0000 0000     # EV_SW / SW_LID               0
E: 13.526538 0000 0000 0000     # ------------ SYN_REPORT (0) ---------- +1100ms
E: 476.391842 0005 0000 0001    # EV_SW / SW_LID               1
E: 476.391842 0000 0000 0000    # ------------ SYN_REPORT (0) ---------- +462865ms
E: 540.518367 0005 0000 0000    # EV_SW / SW_LID               0
E: 540.518367 0000 0000 0000    # ------------ SYN_REPORT (0) ---------- +64127ms
E: 541.900485 0005 0000 0001    # EV_SW / SW_LID               1
E: 541.900485 0000 0000 0000    # ------------ SYN_REPORT (0) ---------- +1382ms
E: 10808.997536 0005 0000 0000  # EV_SW / SW_LID               0
E: 10808.997536 0000 0000 0000  # ------------ SYN_REPORT (0) ---------- +10267097ms