Then change your lircd.conf file to use these codes (eg KEY_PLAYPAUSE instead of PlayPause).
I changes my lircd.conf so it only uses the keycodes from irrecord -l. I mapped the keys from my second remote to KEY_F11 through KEY_F22. These keys are not part of the set of default keys in Kodi as far as I could find out. So I mapped these to the same actions I used to using Lircmap.xml:
<lircmap>
<remote device="harmony_kls_vdr">
<obc1>com2f</obc1>
<obc2>com27</obc2>
<obc3>com28</obc3>
<obc4>com29</obc4>
<obc5>com2a</obc5>
<obc6>com2b</obc6>
<obc7>com2c</obc7>
<obc8>com2d</obc8>
<obc9>com2e</obc9>
<obc10>com30</obc10>
<obc11>com31</obc11>
<obc12>com32</obc12>
</remote>
<remote device="devinput">
<obc1>KEY_F11</obc1>
<obc2>KEY_F12</obc2>
<obc3>KEY_F13</obc3>
<obc4>KEY_F14</obc4>
<obc5>KEY_F15</obc5>
<obc6>KEY_F16</obc6>
<obc7>KEY_F17</obc7>
<obc8>KEY_F18</obc8>
<obc9>KEY_F19</obc9>
<obc10>KEY_F20</obc10>
<obc11>KEY_F21</obc11>
<obc12>KEY_F22</obc12>
</remote>
</lircmap>
Display More
And left my remote.xml unchanged:
<keymap>
<global>
<universalremote>
<obc1>PreviousMenu</obc1>
<obc2>ToggleWatched</obc2>
<obc3>SubtitleDelayMinus</obc3>
<obc4>SubtitleDelayPlus</obc4>
<obc5>XBMC.UpdateLibrary(Video)</obc5>
<obc6>AudioDelayMinus</obc6>
<obc7>AudioDelayPlus</obc7>
<obc9>SendClick(14)</obc9>
<obc10>ContextMenu</obc10>
<obc12>Screenshot</obc12>
</universalremote>
</global>
<FullscreenVideo>
<universalremote>
<obc8>ActivateWindow(subtitlesearch)</obc8>
<obc11>ShowSubtitles</obc11>
<obc10>OSD</obc10>
</universalremote>
<remote>
<back>Seek(-7)</back>
</remote>
</FullscreenVideo>
</keymap>
Display More
So now everything is working again as it should, thanks HiassofT. The only thing that still bugs me is what has changed between LibreELEC 8.0.2 and 8.1.2 that has broken the way my setup used to work? What is different in the way that LibreELEC loads lircd.conf and the way I loaded it with my autostart.sh. The keypresses now seem to be coming from devinput instead of the name of the remote I used in lircd.conf. Does this have something to do with what is written on the Wiki in section LIRC integration with eventlircd / Kodi:
QuoteAlthough, at a first glance, it might seem odd to translate between LIRC, Linux input and then again LIRC events there's a rather simple reason for that: Kodi can receive LIRC events only from a single LIRC socket and with eventlircd collecting all remote events and feeding them to Kodi LibreELEC can support both LIRC-decoded and kernel-decoded remotes without needing the user (or some sophisticated script) having to change the configuration.