Tvheadend

I have a strange issue, where the following things happen:

1. EPG data gets collected as normal, and is presented in the EPG tab
2. I have an autorec created for one of the programs, and it gets added to the upcoming recordings list

So far, nothing strange, but then

3. A few days later, one of the programs (the one I wanted to autorecord) gets deleted from the EPG tab, thus creating a gap.
4. the program also gets removed from the upcoming recordings list

Of course, the recording will fail because it is no longer in the list.

In my case, the program is "Les Revenants" on the Belgian channel "Canvas HD".
On week days, there are 2 episodes, one directly after the other.

In the attached image, you will see there is a recording planned for S1 Afl6 (= episode 6) on Aug 02 and one for S1 Afl8 (= episode 8) on Aug 03.
It is episode 5 and episode 7 that should be just in front of episode 6 and 8 respecively that are missing.

On Aug 02, the program that precedes episode 6 in the list starts at 21:00 and takes 55 minutes, so should run until 21:55.
Episode 6 starts at 22:45, so there is a gap of 50 minutes where Episode 5 should have been (and was, before)

A few notes:

1.
I am 100% sure that both Episode 5 and 7 were in the EPG list before.
I am also 100% sure that they both were in the Upcoming Recordings list.
Every few days I update my spreadsheet with upcoming and finished recordings, with data (starttime, endtime,...) I get from the upcoming recordings list. Both episodes were already on my spreadsheet

2.
I have 3 TVHeadend machines, the 2 episodes are missing from the EPG tab for the other 2 machines as well

3.
One of the other machines is running 4.1-2116~gf59669c, so it is not limited to 4.1-2141~g01c26fc

4.
All 3 have the same language preferences
English
Dutch; Flemish
German

The program that disappeared is originally French. IIRC I have seen a similar issue here or in the forum about disappearing EPG data. I can't find it back right now, but IIRC it had something to do with strange characters from foreign languages.
Since this is originally French, maybe that is relevant here too?

5.
The EPG grabber gets data for the upcoming 7 days. At first, the only data that is visible is the name of the program, start and stop time, and the type of programme: SF-series, 2012.
A few days later, the additional EPG-data comes available: summary of the episode etc...

Maybe it is when the additional data is added that the problem occurs?