Host font loading errors during startup

[dhcp]

Every time I start koreader I see the following errors in the log:

05/26/17-11:39:02 ERROR failed to register crengine font cannot register font <./fonts/host/Caecilia_LT_66_Medium_Italic.ttf>
05/26/17-11:39:02 ERROR failed to register crengine font cannot register font <./fonts/host/Caecilia_LT_67_Cond_Medium.ttf>
05/26/17-11:39:02 ERROR failed to register crengine font cannot register font <./fonts/host/Caecilia_LT_68_Cond_Medium_Italic.ttf>
05/26/17-11:39:02 ERROR failed to register crengine font cannot register font <./fonts/host/Caecilia_LT_75_Bold.ttf>
05/26/17-11:39:02 ERROR failed to register crengine font cannot register font <./fonts/host/Caecilia_LT_76_Bold_Italic.ttf>
05/26/17-11:39:02 ERROR failed to register crengine font cannot register font <./fonts/host/Caecilia_LT_77_Cond_Bold.ttf>
05/26/17-11:39:02 ERROR failed to register crengine font cannot register font <./fonts/host/Caecilia_LT_78_Cond_Bold_Italic.ttf>
05/26/17-11:39:02 ERROR failed to register crengine font cannot register font <./fonts/host/KindleBlackboxBoldItalic.ttf>
05/26/17-11:39:02 ERROR failed to register crengine font cannot register font <./fonts/host/KindleBlackboxItalic.ttf>
05/26/17-11:39:02 ERROR failed to register crengine font cannot register font <./fonts/host/KindleBlackboxRegular.ttf>
05/26/17-11:39:02 ERROR failed to register crengine font cannot register font <./fonts/host/Kindle_MonospacedSymbol.ttf>
05/26/17-11:39:02 ERROR failed to register crengine font cannot register font <./fonts/host/Kindle_Symbol.ttf>
05/26/17-11:39:02 ERROR failed to register crengine font cannot register font <./fonts/host/MTChineseSurrogates.ttf>

As the result, those fonts are not in the list of fonts available to the user (in a submenu 'Choose font'). What can be the problem here?

I am using v2015.11-1023 on PW2IL (B017).