you might find a solution in a VU-related forum, within this forum I only see the solution you used.
This fast channel change feature is help switching channels faster and it is doing this by receiving (+ decoding if channel is encrypted) additional channels in advance.
Simply look at this small part of your logfile
2018/02/11 16:55:50 7913DEA4 c (ecm) dvbapi_local (098C@000000/1262/006D/9F:B2EC12DA5B7E6904060E87C66708BF05): found (69 ms) by "cc_XXXXX" - Eurosport 2 HD
2018/02/11 16:55:52 7913DEA4 c (ecm) dvbapi_local (098C@000000/1014/0089/9F:CE61ADDEF24C4A24B193E1CEEBF9678C): found (154 ms) by "cc_XXXXX" - Spiegel Geschichte HD
2018/02/11 16:55:55 7913DEA4 c (ecm) dvbapi_local (098C@000000/1262/006D/9F:E871B578AA7437A98DC1C812A0B803C5): not found (149 ms) by "cc_XXXXX" - Eurosport 2 HD
2018/02/11 16:55:55 7913DEA4 c (ecm) dvbapi_local (098C@000000/125F/0091/9F:774392FB1B73EB08561D44A442C2017E): found (211 ms) by "cc_XXXXX" - Sky Arts HD
2018/02/11 16:55:55 7913DEA4 c (dvbapi) Demuxer 2 restarting decodingrequests after 0 ms with 1 enabled and 2 disabled ecmpids!
2018/02/11 16:55:55 7913DEA4 c (dvbapi) Demuxer 2 trying to descramble PID 1 CAID 098C PROVID 000000 ECMPID 1A67 ANY CHID PMTPID 0064 VPID 04FF
2018/02/11 16:55:56 7913DEA4 c (ecm) dvbapi_local (098C@000000/1262/006D/9F:E871B578AA7437A98DC1C812A0B803C5): not found (1 ms) by "cc_XXXXX" - Eurosport 2 HD
NDS (at least for german Sky service) sends a new codeword every 6-8 seconds and that is the rate of codewords the server allows - for single subscription, on dual login you can send twice *g*
On this small log you see, that you are sending requests for SID 006D (obvious Eurosport2HD), 0089 (Spiegel Geschichte HD), 0091 (SkyArtsHD) within 5 seconds. And to make it worse obviously, from the log, your Oscam resend the decoding request after 0ms of waiting.
So you are fare of the limit - of course you get errors of decoding failures and rule violation messages.
As long as there is no special FCC/Multituner-setting within Oscam (most likely DVBAPI section) I dont see any solution except switching this feature off.