VERY high memory consumption in Logic 10.4.6 when trimming audio regions

Running Logic 10.4.6 on High Sierra (2011 MacBook Pro 17-inch 2.2 GHz, 16 GB RAM), my Logic sessions consume VERY HIGH amounts of memory (> 50 GB). This seems to be related to editing (cutting and trimming) audio regions.

For example, when I trim a single audio region (randomly, at the beginning or at the end), Logic's memory consumption increases instantly by 600 MB (!). Splitting a single region takes 250 MB. After an hour of editing, the total amount of memory easily exceeds 50 GB.

This seriously affects the overall performance of Logic. Also, the trimming itself takes much longer (> 1 sec) than it used to in previous versions of Logic.

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Some additional information:

The high memory consumption results in high amounts of swapping and disk I/O, and Logic slows down. The memory seems to be 'leaky' as in it is NOT freed when I close the project. I have to restart the entire application in order to free the memory.

The project in question is quite large (30 tracks x 6 hours of audio, 1 Flex pitch track), but in happens with smaller projects as well.