Roberto Martinez believes the defensive deficiencies which undermined his Everton reign are still present at Goodison Park.
Everton have moved to within six points of a Champions League place after winning three and drawing one of their last four games.
The latest win for Ronald Koeman's side was a remarkable 6-3 victory over Bournemouth on Saturday in which Romelu Lukaku scored four.
But Martinez said he saw the same problems which eventually saw his three-year Everton tenure end with the sack last May.
"As a fan you always want to see teams scoring goals and winning games. This performance was about that," Martinez said.
"The only worry is that we had defensive fragilities last year and they cost us too many points.
"The performance was going in the right direction, you are doing everything right and then one action you look fragile.
"I can see the same things still now.
"Three goals in the first 30 minutes and I thought Everton were magnificent, but at 3-2 Bournemouth looked as if they were going to get back into it."
Lukaku took his Everton tally for the season to 17 against Bournemouth before Ross Barkley added a sixth in the final seconds.
Barkley was accused by some of showing disrespect to the Cherries by celebrating before actually tapping the ball into an empty net.
But speaking to Sky's Goals on Sunday programme, Martinez - who was influential in developing Barkley's Everton career - said: "It shows you what Ross is.
"He doesn't do it in a disrespectful manner, he's not trying to take the mickey out of the opponent.
"It's just pure joy. You would see Ross playing in the back yard and that's what he would do with his mates.
"He's effective on the pitch when he's having fun. The quality he has, the physicality with the technical ability, makes him quite unique.
"Of course you always want the perfect footballer to defend well and react well when you lose the ball, but when he has a smile on his face there is a very special talent."
On Lukaku - who Martinez now manages again in his role in charge of the Belgium national team - the Spaniard said: "That's why we made the investment (Â£28million) we did at that point (July 2014).
"We got all the money together and didn't do anything in two windows to bring in that calibre of player at the age of 21.
"At that moment you are trying to manage the player that he can be.
"Now at 23 he is starting to be that player consistently, and as a number nine you are not going to find a better finisher in world football."
Martinez feels Everton can now challenge for a European place, with clubs above them having European and cup commitments during the second half of the season.
"I'm sure Ronald Koeman will look at it and see Manchester United are only just ahead of them and involved in Europe, which is a huge distraction," Martinez said.
"Teams ahead of them are in cups and in Europe, and Everton can use those distractions to their advantage.
"The objective of Ronald Koeman will be to get into Europe, because when you become Everton manager you realise very quickly that you are not at a normal football club."