UPDATE:
even after disconnection of the front audio panel, the issue still happens once in a blue moon:
Left pulseaudio in debug mode for several days after fix:

$ tail -f /tmp/pulseaudio.log | grep is.now 

(3284.252|  96.036) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now plugged in
(3285.280|   1.006) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now unplugged
(4430.108| 136.098) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now plugged in
(4431.133|   1.003) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now unplugged
(65064.220|  35.638) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now plugged in
(65065.244|   1.023) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now unplugged
(163655.996|  23.995) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now plugged in
(163657.020|   1.023) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now unplugged
(166826.748|   0.027) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now plugged in
(166827.772|   0.712) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now unplugged
(170071.580|   2.337) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now plugged in
(170072.605|   0.483) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now unplugged
(170196.156|  63.020) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now plugged in
(170197.180|   1.022) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now unplugged
(173292.956| 110.638) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now plugged in
(173293.980|   1.023) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now unplugged
(405426.784|  13.234) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now plugged in
(405427.804|   0.998) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now unplugged
(501250.208|  28.079) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now plugged in
(501251.228|   1.018) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now unplugged
(508205.532|   1.475) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now plugged in
(508206.556|   1.022) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now unplugged
(576198.464|  60.134) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now plugged in
(576199.484|   1.018) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now unplugged
(577215.964|   3.252) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now plugged in
(577216.992|   0.726) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now unplugged
(577250.780|  26.097) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now plugged in
(577251.804|   1.022) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now unplugged
(577291.740|   0.147) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now plugged in
(577292.764|   0.515) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now unplugged
(577495.964|  54.201) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now plugged in
(577496.988|   1.023) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now unplugged
(578591.196| 137.355) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now plugged in
(578592.220|   1.022) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now unplugged
(589797.436|   1.779) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now plugged in
(589798.460|   1.022) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now unplugged
(589802.556|   4.095) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now plugged in
(589803.580|   1.022) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now unplugged
(593142.972| 274.353) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now plugged in
(593143.996|   1.002) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now unplugged
(593435.804| 267.849) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now plugged in
(593436.832|   1.005) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now unplugged
(594411.680|  25.302) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now plugged in
(594412.700|   1.001) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now unplugged
(594960.540|  37.896) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now plugged in
(594961.564|   1.002) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now unplugged