Pendrive/SD card file copy

Damn, such a facepalm. There is a lot of stuff plugged into the PI already, and it is hard to reach the free USB ports, so I used a USB A male to USB A female extender cable. And when I checked the journal, I could see this:

Sep 16 08:05:50 OpenHAB kernel: usb 1-1.4: new high-speed USB device number 31 using dwc_otg
Sep 16 08:05:50 OpenHAB kernel: usb 1-1.4: New USB device found, idVendor=090c, idProduct=1000
Sep 16 08:05:50 OpenHAB kernel: usb 1-1.4: New USB device strings: Mfr=1, Product=2, SerialNumber=3
Sep 16 08:05:50 OpenHAB kernel: usb 1-1.4: Product: USB DISK
Sep 16 08:05:50 OpenHAB kernel: usb 1-1.4: Manufacturer: SMI Corporation
Sep 16 08:05:50 OpenHAB kernel: usb 1-1.4: SerialNumber: AA04012700009117
Sep 16 08:05:50 OpenHAB kernel: usb-storage 1-1.4:1.0: USB Mass Storage device detected
Sep 16 08:05:50 OpenHAB kernel: scsi host0: usb-storage 1-1.4:1.0
Sep 16 08:05:50 OpenHAB systemd-udevd[28283]: failed to execute '/lib/udev/mtp-probe' 'mtp-probe /sys/devices/platform/soc/3f980000.usb/usb1/1-1/1-1.4 1 31': No such file or directory
Sep 16 08:05:51 OpenHAB kernel: usb 1-1.4: USB disconnect, device number 31

And this section kept repeating. Now I removed this damn extender cable, and now it appears to be working:

Sep 16 08:13:20 OpenHAB kernel: usb 1-1.4: new high-speed USB device number 88 using dwc_otg
Sep 16 08:13:20 OpenHAB systemd-udevd[29074]: failed to execute '/lib/udev/mtp-probe' 'mtp-probe /sys/devices/platform/soc/3f980000.usb/usb1/1-1/1-1.4 1 88': No such file or directory
Sep 16 08:13:20 OpenHAB kernel: usb 1-1.4: New USB device found, idVendor=0781, idProduct=5591
Sep 16 08:13:20 OpenHAB kernel: usb 1-1.4: New USB device strings: Mfr=1, Product=2, SerialNumber=3
Sep 16 08:13:20 OpenHAB kernel: usb 1-1.4: Product: Ultra USB 3.0
Sep 16 08:13:20 OpenHAB kernel: usb 1-1.4: Manufacturer: SanDisk
Sep 16 08:13:20 OpenHAB kernel: usb 1-1.4: SerialNumber: 4C531001490423104554
Sep 16 08:13:20 OpenHAB kernel: usb-storage 1-1.4:1.0: USB Mass Storage device detected
Sep 16 08:13:20 OpenHAB kernel: scsi host0: usb-storage 1-1.4:1.0
Sep 16 08:13:22 OpenHAB kernel: scsi 0:0:0:0: Direct-Access SanDisk Ultra USB 3.0 1.00 PQ: 0 ANSI: 6
Sep 16 08:13:22 OpenHAB kernel: sd 0:0:0:0: Attached scsi generic sg0 type 0
Sep 16 08:13:22 OpenHAB kernel: sd 0:0:0:0: [sda] 121307136 512-byte logical blocks: (62.1 GB/57.8 GiB)
Sep 16 08:13:22 OpenHAB kernel: sd 0:0:0:0: [sda] Write Protect is off
Sep 16 08:13:22 OpenHAB kernel: sd 0:0:0:0: [sda] Mode Sense: 43 00 00 00
Sep 16 08:13:22 OpenHAB kernel: sd 0:0:0:0: [sda] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
Sep 16 08:13:22 OpenHAB kernel: sda: sda1
Sep 16 08:13:22 OpenHAB kernel: sd 0:0:0:0: [sda] Attached SCSI removable disk

Although I don't see this being mounted automatically to any path.

Let me tell you want I am planning to use this for: my dad likes to listen to recorded programmes from the radio on his phone. At the moment, he has an old Samsung phone which still has an FM radio and only uses that to record radio programmes. There are no such services I know of where you can listen to past radio programmes where I live.
I already have have a working Node-Red flow which can be programmed to record radio programmes (from internet radio source) and save them as mp3 on the PI. This piece I am working on should automatically copy these mp3 files to his phone when it is plugged into the PI. This is why I wanted to see if new USB devices are plugged in. But I realized that mobile phones will not be detected and USB mass storage devices immediately. Currently he has a Huawei Pxx phone. He is >80 so I need a solution that is plug and play.

That might be because you aren't using standard Raspbian (at least that is what I deduce from the log). That might also be a factor in what was causing the SEGV error with the faulty cable. Even with a faulty cable usb-detection should not crash, assuming that is what was happening.