Hello @Stm32_dev and welcome to the Community :),
I apologize for my late reply.
Thank you for bringing this issue to our attention. I confirm the issue when using STM32CubeIDE 1.15.0 and I reported internally.
It is mentioned in the release note projects of I-CUBE-LRWAN that the development toolchain and compiler used for this package is STM32CubeIDE v1.6.1. For that please try to update the STM32CubeIDE toolchain.

May these posts can help you: Post1 and Post2.
Internal ticket number: 181244 (This is an internal tracking number and is not accessible or usable by customers).
Thank you.
Kaouthar
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