nfcpy: Connection timed out after first connection to ACR122U-A9

I have just purchased a ACR122U-A9 which seems to work perfectly the first time after plugging it in.

Running python -m nfc on a raspberry pi with raspbian stretch yields:

This is the 1.0.3 version of nfcpy run in Python 3.5.3
on Linux-4.14.79-v7+-armv7l-with-debian-9.6
I'm now searching your system for contactless devices
** found ACS ACR122U PN532v1.6 at usb:001:018
I'm not trying serial devices because you haven't told me
-- add the option '--search-tty' to have me looking
-- but beware that this may break other serial devs

Afterwards, however, nfcpy seems to not find the reader again:

~/prg/nfc $ venv/bin/python -m nfc -vvv
This is the 1.0.3 version of nfcpy run in Python 3.5.3
on Linux-4.14.79-v7+-armv7l-with-debian-9.6
I'm now searching your system for contactless devices
DEBUG:nfc.clf.transport:using libusb-1.0.21
DEBUG:nfc.clf.transport:path matches '^(usb|)$'
INFO:nfc.clf:searching for reader on path usb:001:017
DEBUG:nfc.clf.transport:using libusb-1.0.21
DEBUG:nfc.clf.transport:path matches '^usb(:[0-9]{1,3})(:[0-9]{1,3})?$'
DEBUG:nfc.clf.device:loading acr122 driver for usb:072f:2200
Level 9:nfc.clf.transport:>>> 6f050000000000000000ff00480000
Level 9:nfc.clf.transport:<<< 800a000000000002810041435231323255323136
DEBUG:nfc.clf.acr122:initialize ACR122U216
DEBUG:nfc.clf.acr122:CCID ICC-POWER-ON
Level 9:nfc.clf.transport:>>> 62000000000000000000
Level 9:nfc.clf.transport:<<< 800200000000000081003b00
DEBUG:nfc.clf.acr122:Set PICC Operating Parameters
Level 9:nfc.clf.transport:>>> 6f050000000000000000ff00517f00
DEBUG:nfc.clf.device:[Errno 110] Connection timed out
I'm not trying serial devices because you haven't told me
-- add the option '--search-tty' to have me looking
-- but beware that this may break other serial devs
Sorry, but I couldn't find any contactless device

It is still listed in the usb subsystem, though:

~/prg/nfc $ lsusb
Bus 001 Device 018: ID 072f:2200 Advanced Card Systems, Ltd ACR122U
Bus 001 Device 004: ID 0424:7800 Standard Microsystems Corp. 
Bus 001 Device 003: ID 0424:2514 Standard Microsystems Corp. USB 2.0 Hub
Bus 001 Device 002: ID 0424:2514 Standard Microsystems Corp. USB 2.0 Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

dmesg does not report anything after the usual device-just-got-plugged-in stuff:

[4845587.420638] usb 1-1.3: new full-speed USB device number 18 using dwc_otg
[4845587.562875] usb 1-1.3: New USB device found, idVendor=072f, idProduct=2200
[4845587.562890] usb 1-1.3: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[4845587.562899] usb 1-1.3: Product: ACR122U PICC Interface
[4845587.562907] usb 1-1.3: Manufacturer: ACS

Only after pulling the USB plug and plugging the reader back in, it can be used once again before posing the same problem.

I set up a brand new virtual environment with fresh packages for the tests.

Is this a known problem and are there any workarounds? Would updating the distro help?

Thanks for any hints, cheers, Andy.