GES 1.16.0, caps renegotiation problem

[David Ing]

I am running a GESTimeline inside of a GstPipeline.  I am attaching an SVG
file which illustrates the pipeline when it enters it's READY state.

Soon after the the pipeline begins PLAYING, the muxers receive a request to
re-negotiate the caps.

*My first question is:*  Is it normal to re-negotiate caps after a pipeline
is already playing?  (This doesn't seem right to me.)

*My second question is:*  How can I determine which element is trying to
renegotiate the caps after the pipeline is already PLAYING?

BTW:  Here are the logs I see as it relates to the caps re-negotation error.

19-07-24T15:44:36.530562 INFO    pan CompositionJob.cpp:123 Pipeline
state changed from PAUSED to PLAYING in 0.000 seconds.
19-07-24T15:44:36.925546 WARNING qtmux gstqtmux.c:5118 pad video_0
refused renegotiation to 0x7f7080003000 A
19-07-24T15:44:36.925673 WARNING qtmux gstqtmux.c:5118 pad video_0
refused renegotiation to 0x7f7080003000 A
19-07-24T15:44:36.925725 WARNING GST_PADS gstpad.c:4230 could not send
sticky events
19-07-24T15:44:36.927847 WARNING qtmux gstqtmux.c:5118 pad video_0
refused renegotiation to 0x7f7080003000 A
19-07-24T15:44:36.927973 WARNING qtmux gstqtmux.c:5118 pad video_0
refused renegotiation to 0x7f7080003000 A
19-07-24T15:44:36.928039 WARNING qtmux gstqtmux.c:5118 pad video_0
refused renegotiation to 0x7f7080003000 A
19-07-24T15:44:36.932935 WARNING qtdemux qtdemux.c:6607 error:
Internal data stream error.
19-07-24T15:44:36.933041 WARNING qtdemux qtdemux.c:6607 error:
streaming stopped, reason not-negotiated (-4)
19-07-24T15:44:36.934955 ERROR   pan CompositionJob.cpp:282
GST_MESSAGE_ERROR received from element qtdemux5 at position
5465466666: Internal data stream error.
../gst-plugins-good/gst/isomp4/qtdemux.c(6607): gst_qtdemux_loop ():
/GstPipeline:pipeline/GESTimeline:gestimeline0/GESVideoTrack:gesvideotrack0/NleComposition:video_nlecomposition1/GstBin:current-bin/NleSource:GESVideoUriSource:nlesource4/GstBin:videosrcbin/GstURIDecodeBin:uridecodebin2/GstDecodeBin:decodebin9/GstQTDemux:qtdemux5:
streaming stopped, reason not-negotiated (-4)
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