Do you believe it is prudent and/or proactive to put a little of the fungicide down? I have seen thin, stringy-like fungus beneath the mulch. 

Background: This palm continues to shoot out new growth but the fronds pretty quickly get this splotchy browning and start to look necrotic. About 3 months ago, I posted in this forum and got some good feedback to plant potassium spikes, which I did. Someone else said to apply a system fungicide. I have fertilized with a good palm fertilizer and continue to use potassium spikes, but the tree just seems weak, in general.  Like the fronds seem to be drooping even more than in the past. Thank you for any advice, I am open ears!

 

 

This is a previous close-up of it. In July, I pruned off the diseased/dead fronds but alas, they seem to be returning.

Usually it's a good idea to post followup on the old thread, that way people can see the earlier photos and description:

 

As a soil drench it is labeled for 8-16oz of 336F per 100 gallons of water.  They say 0.25-3 pints of mixture per square foot.  As a general rule you cover the "canopy area" with fertilizer and fungicides.  So in your case it may be 8 feet overall diameter = 50sqft.  Somewhere between 12.5 - 150 pints is per the recommendation, but this is really geared towards plants in pots.  150 pints is a whopping 19 gallons of mix, which seems way too much.  I'd probably do a 5 gallon bucket with 1oz of Clearys 3336F and mix some liquid fertilizer (Miracle Gro = 2.5tsp per 5gal) in at the same time.  Spread it out reasonably evenly under the canopy with maybe 50% of it in the mulched area.  I say that because if it's been in the ground for only a year then a lot of the roots are still in that mulched circle and haven't moved out too far into the surrounding dirt.

One other thing I didn't notice on the first post is that the mulch appears to be mounded up over the trunk.  Generally you want mulch to come up "near" the trunk but not on top of it.  Too much moisture at the trunk can promote rot.  It's also possible that the palm was planted too deep, which might be contributing to the problem.  Here's the best resource for planting depth I've found, written by an IPS director and PalmTalk member Len Geiger:  http://www.marriedtoplants.com/palms/palm-tree-growing-tips-mounding/

Thank you so much for the thorough advice. 

It seems that palm is having troubles with too much moisture at the roots.  Potassium deficiency would initially display as translucent spotting,  not dark spotting.  I would focus on applying a systemic fungicide drench.  Fertilizers with a high nitrogen to potassium ratio or a lack of available calcium in the soil will exacerbate the spotting.