I’m unsure if it is fixed by IKEA in a new hardware revision. There has been no new software/firmware for the current version.
All I know is, the battery lifetime is too short. You will have to replace every 2 (max 5) months, depending on your network/activity of the door/window.
For me personally, that is way too short.
I bought like 15 parasolls, some are not even mounted because of this issue.
If I have to choose again I would not buy them although I’m not sure of a good replacement. Maybe the Tuya Zigbee version?
Ideally it would be based on Zigbee/Zwave, using AAA or AA batteries, have a battery lifespan of 1 year+.
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Slightly offtopic, looking into an alternative:
Here are 2 Tuya/EWeLink zigbee doorsensors compared: Tuya door sensor - external sensor
Some info from another topic: A list of door sensor / reed sensor hacks! (Aqara, Xiaomi, others)
At least I do not see any battery issues in these topics 
Both Tuya ZY-ZD02 and EWeLink MC500A/MC510A-A002 on AliExpress for around 5 euro’s. For me the EWeLink looks more promising since it’s a single PCB and somebody already took to time to measure power consumption. I think I will buy 1 of each and compare them next to the Parasolls.