David Moyes is not quite sure what is causing West Ham's crippling vulnerability at the start of the second half of matches, but at least he knows what is not.
"It's not as if we're going in and eating a pie at half-time and coming out feeling rubbish," the Hammers boss said, after watching his team concede in the first 15 minutes after the break for the 16th time this calendar year.
On this occasion, the goal was both needless and costly, Konstantinos Mavropanos's clanger allowing Odsonne Edouard to earn visitors Palace a 1-1 draw after Mohammed Kudus had opened the scoring after 13 minutes.
But it was not only post-interval that the hosts were lethargic; this something of a Sunday snooze throughout, one that had even Palace boss Roy Hodgson conceding was unlikely to trouble the top end of the Match of the Day 2 running order.
With Palace on the road, in poor form and crippled by injury, the onus was on West Ham to deliver the game's spark, but after crafting a fine move for Kudus's opener, Moyes was left to bemoan his side's lack of invention.
"We're playing safe a little bit, I want us to take more risks," he said. "We couldn't really play with enough personality, we couldn't get the atmosphere going. We were sort of down and we couldn't get things lifted."
So, if not steak bakes or Cornish pasties, what might have been to blame for such a sluggish display? It did not help that Jarrod Bowen looked rusty on his return, following a three-week absence with a minor knee injury, the forward heading straight at Sam Johnstone with a glorious chance to snatch yet another late winner.
The more obvious answer lies in Serbia, where the Hammers played Backa Topola in the Europa League on Thursday, only landing in London on Friday afternoon, little more than 48 hours before kick-off here.
Moyes, in fairness, was reluctant to use the excuse, pointing out that a number of first-team regulars had either spent most of the night on the bench or on their sofas.
But the suspicion that none of the fringe mob had done much to press their case was confirmed here, as Moyes did not turn to his bench until the 89th minute, and even then only to send on midfielder Pablo Fornals. "I felt the boys on the pitch were the ones who gave me the best chance of getting something from the game," he said.
On Friday, the manager had been asked about the depth of his squad, and there was something to be read into the fact he quickly affirmed himself content with the number of bodies available, without giving mention to the quality.
Summer improvements have clearly made West Ham a better team, but the gap between the best and the rest is obvious and Moyes's apparent lack of faith in some of his reserves is a concern.
They have been navigating a Thursday-Sunday schedule for much of the season already, with Moyes using the midweek element for a degree of rotation.
The next month, though, offers no soft openings: in three midweeks between now and Christmas, West Ham play Tottenham in the League, face a vital shootout with Freiburg for top spot in the Europa League and then travel to Anfield for a Carabao Cup quarter-final.
Food for thought, then, for Moyes, who must ensure this kind of slumber does not set in.
